Repository: fniessink/toisto (language: python)

Issue:
Make progress file case insensitive so that case changes in labels do not impact progress



Discussion / hints:

Fix patch:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 588b11e6..c2a78789 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## [Unreleased]
 
+### Fixed
+
+- In the topic files, only have words with capitals when they start a sentence or are always written with an initial capital. Unfortunately, this is a backwards incompatible change and progress information is lost. Fixes [#242](https://github.com/fniessink/toisto/issues/242).
 ### Added
 
 - Allow for specifying the meaning of concepts that have no label in a language. Closes [#138](https://github.com/fniessink/toisto/issues/138).
diff --git a/docs/software.md b/docs/software.md
index 254283fe..875c8d21 100644
--- a/docs/software.md
+++ b/docs/software.md
@@ -512,10 +512,10 @@ When the program is stopped, progress is saved in a file named `.toisto-progress
 
 ```json
 {
-    "to read:nl:fi:Lezen:translate": {
+    "to read:nl:fi:lezen:translate": {
         "count": 2
     },
-    "eye:nl:fi:Het oog:translate": {
+    "eye:nl:fi:het oog:translate": {
         "start": "2023-02-25T17:34:37",
         "end": "2023-02-25T17:35:37",
         "skip_until": "2023-02-26T17:40:37",
diff --git a/src/toisto/model/language/concept.py b/src/toisto/model/language/concept.py
index c77b4245..a5fa4743 100644
--- a/src/toisto/model/language/concept.py
+++ b/src/toisto/model/language/concept.py
@@ -4,6 +4,7 @@
 
 from collections.abc import Iterable
 from dataclasses import dataclass, field
+from functools import cached_property
 from typing import ClassVar, NewType, cast, get_args
 
 from . import Language
@@ -94,7 +95,7 @@ def __getattr__(self, attribute: str) -> Concepts:
         """Forward properties to related concepts."""
         return getattr(self.related_concepts, attribute)
 
-    @property
+    @cached_property
     def base_concept(self) -> Concept:
         """Return the base concept of this concept."""
         return self.related_concepts.parent.base_concept if self.related_concepts.parent else self
diff --git a/src/toisto/model/quiz/progress.py b/src/toisto/model/quiz/progress.py
index cbc50c01..6695f9c8 100644
--- a/src/toisto/model/quiz/progress.py
+++ b/src/toisto/model/quiz/progress.py
@@ -22,11 +22,11 @@ def __init__(self, progress_dict: dict[str, dict[str, str | int]], topics: Topic
 
     def increase_retention(self, quiz: Quiz) -> None:
         """Increase the retention of the quiz."""
-        self.__progress_dict.setdefault(quiz.key(), Retention()).increase()
+        self.__progress_dict.setdefault(quiz.key, Retention()).increase()
 
     def reset_retention(self, quiz: Quiz) -> None:
         """Reset the retention of the quiz."""
-        self.__progress_dict.setdefault(quiz.key(), Retention()).reset()
+        self.__progress_dict.setdefault(quiz.key, Retention()).reset()
 
     def next_quiz(self) -> Quiz | None:
         """Return the next quiz."""
@@ -42,7 +42,7 @@ def next_quiz(self) -> Quiz | None:
 
     def get_retention(self, quiz: Quiz) -> Retention:
         """Return the quiz retention."""
-        return self.__progress_dict.get(quiz.key(), Retention())
+        return self.__progress_dict.get(quiz.key, Retention())
 
     def __is_eligible(self, quiz: Quiz) -> bool:
         """Return whether the quiz is not silenced and not the current quiz."""
@@ -55,7 +55,7 @@ def __has_concept_in_progress(self, quiz: Quiz) -> bool:
 
     def __in_progress(self, quiz: Quiz) -> bool:
         """Return whether the quiz has been presented to the user before."""
-        return quiz.key() in self.__progress_dict
+        return quiz.key in self.__progress_dict
 
     def __unblocked_quizzes(self, quizzes: Quizzes, eligible_quizzes: Quizzes) -> Quizzes:
         """Return the quizzes that are not blocked by other quizzes.
diff --git a/src/toisto/model/quiz/quiz.py b/src/toisto/model/quiz/quiz.py
index 5faa9430..e1cae238 100644
--- a/src/toisto/model/quiz/quiz.py
+++ b/src/toisto/model/quiz/quiz.py
@@ -90,7 +90,7 @@ class Quiz:
     def __post_init__(self) -> None:
         """Initialize calculated attributes."""
         # The dataclass is frozen, so some magic is needed to set the hash attribute.
-        super().__setattr__("_hash", hash(self.key()))
+        super().__setattr__("_hash", hash(self.key))
 
     def __hash__(self) -> int:
         """Return a hash using the same attributes as used for testing equality."""
@@ -98,12 +98,13 @@ def __hash__(self) -> int:
 
     def __eq__(self, other: object) -> bool:
         """Return whether this quiz is equal to the other."""
-        return self.key() == other.key() if isinstance(other, self.__class__) else False
+        return self.key == other.key if isinstance(other, self.__class__) else False
 
     def __ne__(self, other: object) -> bool:
         """Return whether this quiz is not equal to the other."""
         return not self == other
 
+    @cached_property
     def key(self) -> str:
         """Return a string version of the quiz that can be used as key in the progress dict."""
         concept_id = self.concept.base_concept.concept_id
diff --git a/src/toisto/persistence/topics.py b/src/toisto/persistence/topics.py
index a9c9ca80..ec779b02 100644
--- a/src/toisto/persistence/topics.py
+++ b/src/toisto/persistence/topics.py
@@ -7,6 +7,7 @@
 from ..metadata import NAME, TOPIC_JSON_FILES
 from ..model.language import Language
 from ..model.language.cefr import CommonReferenceLevel
+from ..model.language.concept import ConceptId, ConceptIds
 from ..model.language.concept_factory import ConceptFactory
 from ..model.quiz.quiz_factory import QuizFactory
 from ..model.quiz.topic import Topic, Topics
@@ -30,6 +31,7 @@ def load_topics(  # noqa: PLR0913
     else:
         topic_files.extend(TOPIC_JSON_FILES)
     quiz_factory = QuizFactory(target_language, source_language)
+    registry = ConceptIdRegistry(argument_parser)
     for topic_file in topic_files:
         concepts = []
         topic_quizzes = set()
@@ -41,6 +43,36 @@ def load_topics(  # noqa: PLR0913
                 concepts.append(concept)
                 topic_quizzes.update(quiz_factory.create_quizzes(concept))
         except Exception as reason:  # noqa: BLE001
-            return argument_parser.error(f"{NAME} cannot read topic {topic_file}: {reason}.\n")
+            argument_parser.error(f"{NAME} cannot read topic {topic_file}: {reason}.\n")
+        concept_ids = tuple({quiz.concept.base_concept.concept_id for quiz in topic_quizzes})
+        registry.check_concept_ids(concept_ids, topic_file)
+        registry.register_concept_ids(concept_ids, topic_file)
         topics.add(Topic(topic_file.stem, tuple(concepts), topic_quizzes))
     return Topics(topics)
+
+
+class ConceptIdRegistry:
+    """Registry to check the uniqueness of concept identifiers across topic files."""
+
+    def __init__(self, argument_parser: ArgumentParser) -> None:
+        self.argument_parser = argument_parser
+        self.topic_files_by_concept_id: dict[ConceptId, pathlib.Path] = {}
+
+    def check_concept_ids(self, concept_ids: ConceptIds, topic_file: pathlib.Path) -> None:
+        """Check that the concept ids are unique."""
+        for concept_id in concept_ids:
+            self._check_concept_id(concept_id, topic_file)
+
+    def _check_concept_id(self, concept_id: ConceptId, topic_file: pathlib.Path) -> None:
+        """Check that the concept id is unique."""
+        if concept_id in self.topic_files_by_concept_id:
+            other_topic_file = self.topic_files_by_concept_id[concept_id]
+            self.argument_parser.error(
+                f"{NAME} cannot read topic {topic_file}: concept identifier '{concept_id}' also occurs in topic "
+                f"'{other_topic_file}'.\nConcept identifiers must be unique across topic files.\n",
+            )
+
+    def register_concept_ids(self, concept_ids: ConceptIds, topic_file: pathlib.Path) -> None:
+        """Register the concept ids."""
+        for concept_id in concept_ids:
+            self.topic_files_by_concept_id[concept_id] = topic_file
diff --git a/src/topics/adverbs.json b/src/topics/adverbs.json
index eb6ddd0c..c7a86691 100644
--- a/src/topics/adverbs.json
+++ b/src/topics/adverbs.json
@@ -3,8 +3,8 @@
         "level": {
             "A1": ["EP", "OD"]
         },
-        "en": "There",
-        "fi": "Tuossa",
-        "nl": "Daar"
+        "en": "there",
+        "fi": "tuossa",
+        "nl": "daar"
     }
 }
\ No newline at end of file
diff --git a/src/topics/animals.json b/src/topics/animals.json
index 6d3f1cce..26002c84 100644
--- a/src/topics/animals.json
+++ b/src/topics/animals.json
@@ -8,14 +8,14 @@
             ]
         },
         "singular": {
-            "en": "Animal",
-            "fi": "Eläin",
-            "nl": "Het dier"
+            "en": "animal",
+            "fi": "eläin",
+            "nl": "het dier"
         },
         "plural": {
-            "en": "Animals",
-            "fi": "Eläimet",
-            "nl": "De dieren"
+            "en": "animals",
+            "fi": "eläimet",
+            "nl": "de dieren"
         }
     },
     "pet": {
@@ -34,20 +34,20 @@
             ]
         },
         "singular": {
-            "en": "Pet",
+            "en": "pet",
             "fi": [
-                "Lemmikki",
-                "Kotieläin"
+                "lemmikki",
+                "kotieläin"
             ],
-            "nl": "Het huisdier"
+            "nl": "het huisdier"
         },
         "plural": {
-            "en": "Pets",
+            "en": "pets",
             "fi": [
-                "Lemmikit",
-                "Kotieläimet"
+                "lemmikit",
+                "kotieläimet"
             ],
-            "nl": "De huisdieren"
+            "nl": "de huisdieren"
         }
     },
     "dog": {
@@ -59,14 +59,14 @@
             ]
         },
         "singular": {
-            "en": "Dog",
-            "fi": "Koira",
-            "nl": "De hond"
+            "en": "dog",
+            "fi": "koira",
+            "nl": "de hond"
         },
         "plural": {
-            "en": "Dogs",
-            "fi": "Koirat",
-            "nl": "De honden"
+            "en": "dogs",
+            "fi": "koirat",
+            "nl": "de honden"
         }
     },
     "cat": {
@@ -78,14 +78,14 @@
             ]
         },
         "singular": {
-            "en": "Cat",
-            "fi": "Kissa",
-            "nl": "De kat"
+            "en": "cat",
+            "fi": "kissa",
+            "nl": "de kat"
         },
         "plural": {
-            "en": "Cats",
-            "fi": "Kissat",
-            "nl": "De katten"
+            "en": "cats",
+            "fi": "kissat",
+            "nl": "de katten"
         }
     },
     "rhino": {
@@ -103,14 +103,14 @@
             ]
         },
         "singular": {
-            "en": "Rhinoceros|Rhino",
-            "fi": "Sarvikuono",
-            "nl": "De neushoorn"
+            "en": "rhinoceros|rhino",
+            "fi": "sarvikuono",
+            "nl": "de neushoorn"
         },
         "plural": {
-            "en": "Rhinoceroses|Rhinos",
-            "fi": "Sarvikuonot",
-            "nl": "De neushoorns"
+            "en": "rhinoceroses|rhinos",
+            "fi": "sarvikuonot",
+            "nl": "de neushoorns"
         }
     },
     "elephant": {
@@ -119,20 +119,20 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Elephant",
+            "en": "elephant",
             "fi": [
-                "Elefantti",
-                "Norsu"
+                "elefantti",
+                "norsu"
             ],
-            "nl": "De olifant"
+            "nl": "de olifant"
         },
         "plural": {
-            "en": "Elephants",
+            "en": "elephants",
             "fi": [
-                "Elefantit",
-                "Norsut"
+                "elefantit",
+                "norsut"
             ],
-            "nl": "De olifanten"
+            "nl": "de olifanten"
         }
     },
     "mouse": {
@@ -141,14 +141,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Mouse",
-            "fi": "Hiiri",
-            "nl": "De muis"
+            "en": "mouse",
+            "fi": "hiiri",
+            "nl": "de muis"
         },
         "plural": {
-            "en": "Mice",
-            "fi": "Hiiret",
-            "nl": "De muizen"
+            "en": "mice",
+            "fi": "hiiret",
+            "nl": "de muizen"
         }
     },
     "duck": {
@@ -159,14 +159,14 @@
             ]
         },
         "singular": {
-            "en": "Duck",
-            "fi": "Ankka",
-            "nl": "De eend"
+            "en": "duck",
+            "fi": "ankka",
+            "nl": "de eend"
         },
         "plural": {
-            "en": "Ducks",
-            "fi": "Ankat",
-            "nl": "De eenden"
+            "en": "ducks",
+            "fi": "ankat",
+            "nl": "de eenden"
         }
     },
     "goose": {
@@ -175,14 +175,14 @@
             "none": "EP"
         },
         "singular": {
-            "en": "Goose",
-            "fi": "Hanhi",
-            "nl": "De gans"
+            "en": "goose",
+            "fi": "hanhi",
+            "nl": "de gans"
         },
         "plural": {
-            "en": "Geese",
-            "fi": "Hanhet",
-            "nl": "De ganzen"
+            "en": "geese",
+            "fi": "hanhet",
+            "nl": "de ganzen"
         }
     },
     "bird": {
@@ -193,14 +193,14 @@
             ]
         },
         "singular": {
-            "en": "Bird",
-            "fi": "Lintu",
-            "nl": "De vogel"
+            "en": "bird",
+            "fi": "lintu",
+            "nl": "de vogel"
         },
         "plural": {
-            "en": "Birds",
-            "fi": "Linnut",
-            "nl": "De vogels"
+            "en": "birds",
+            "fi": "linnut",
+            "nl": "de vogels"
         }
     },
     "horse": {
@@ -212,14 +212,14 @@
             ]
         },
         "singular": {
-            "en": "Horse",
-            "fi": "Hevonen",
-            "nl": "Het paard"
+            "en": "horse",
+            "fi": "hevonen",
+            "nl": "het paard"
         },
         "plural": {
-            "en": "Horses",
-            "fi": "Hevoset",
-            "nl": "De paarden"
+            "en": "horses",
+            "fi": "hevoset",
+            "nl": "de paarden"
         }
     },
     "cow": {
@@ -227,14 +227,14 @@
             "A1": "OD"
         },
         "singular": {
-            "en": "Cow",
-            "fi": "Lehmä",
-            "nl": "De koe"
+            "en": "cow",
+            "fi": "lehmä",
+            "nl": "de koe"
         },
         "plural": {
-            "en": "Cows",
-            "fi": "Lehmät",
-            "nl": "De koeien"
+            "en": "cows",
+            "fi": "lehmät",
+            "nl": "de koeien"
         }
     },
     "pig": {
@@ -245,20 +245,20 @@
             ]
         },
         "singular": {
-            "en": "Pig",
+            "en": "pig",
             "fi": [
-                "Possu",
-                "Sika"
+                "possu",
+                "sika"
             ],
-            "nl": "Het varken"
+            "nl": "het varken"
         },
         "plural": {
-            "en": "Pigs",
+            "en": "pigs",
             "fi": [
-                "Possut",
-                "Siat"
+                "possut",
+                "siat"
             ],
-            "nl": "De varkens"
+            "nl": "de varkens"
         }
     },
     "deer": {
@@ -269,14 +269,34 @@
             ]
         },
         "singular": {
-            "en": "Deer",
-            "fi": "Peura",
-            "nl": "Het hert"
+            "en": "deer",
+            "fi": "peura",
+            "nl": "het hert"
         },
         "plural": {
-            "en": "Deer",
-            "fi": "Peurat",
-            "nl": "De herten"
+            "en": "deer",
+            "fi": "peurat",
+            "nl": "de herten"
+        }
+    },
+    "reindeer": {
+        "level": {
+            "B2": "OD",
+            "none": "EP"
+        },
+        "roots": {
+            "en": "deer",
+            "nl": ["to run", "animal"]
+        },
+        "singular": {
+            "en": "reindeer;singular",
+            "fi": "poro",
+            "nl": "rendier"
+        },
+        "plural": {
+            "en": "reindeer;plural",
+            "fi": "porot",
+            "nl": "rendieren"
         }
     },
     "bear": {
@@ -285,14 +305,14 @@
             "B2": "OD"
         },
         "singular": {
-            "en": "Bear",
-            "fi": "Karhu",
-            "nl": "De beer"
+            "en": "bear",
+            "fi": "karhu",
+            "nl": "de beer"
         },
         "plural": {
-            "en": "Bears",
-            "fi": "Karhut",
-            "nl": "De beren"
+            "en": "bears",
+            "fi": "karhut",
+            "nl": "de beren"
         }
     },
     "sheep": {
@@ -303,14 +323,14 @@
             ]
         },
         "singular": {
-            "en": "Sheep",
-            "fi": "Lammas",
-            "nl": "Het schaap"
+            "en": "sheep",
+            "fi": "lammas",
+            "nl": "het schaap"
         },
         "plural": {
-            "en": "Sheep",
-            "fi": "Lampaat",
-            "nl": "De schapen"
+            "en": "sheep",
+            "fi": "lampaat",
+            "nl": "de schapen"
         }
     },
     "crab": {
@@ -321,14 +341,14 @@
             ]
         },
         "singular": {
-            "en": "Crab",
-            "fi": "Rapu",
-            "nl": "De krab"
+            "en": "crab",
+            "fi": "rapu",
+            "nl": "de krab"
         },
         "plural": {
-            "en": "Crabs",
-            "fi": "Ravut",
-            "nl": "De krabben"
+            "en": "crabs",
+            "fi": "ravut",
+            "nl": "de krabben"
         }
     },
     "spider": {
@@ -337,14 +357,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Spider",
-            "fi": "Hämähäkki",
-            "nl": "De spin"
+            "en": "spider",
+            "fi": "hämähäkki",
+            "nl": "de spin"
         },
         "plural": {
-            "en": "Spiders",
-            "fi": "Hämähäkit",
-            "nl": "De spinnen"
+            "en": "spiders",
+            "fi": "hämähäkit",
+            "nl": "de spinnen"
         }
     },
     "rabbit": {
@@ -356,25 +376,25 @@
         },
         "singular": {
             "en": [
-                "Rabbit",
-                "Bunny"
+                "rabbit",
+                "bunny"
             ],
             "fi": [
-                "Jänis",
-                "Pupu"
+                "jänis",
+                "pupu"
             ],
-            "nl": "Het konijn"
+            "nl": "het konijn"
         },
         "plural": {
             "en": [
-                "Rabbits",
-                "Bunnies"
+                "rabbits",
+                "bunnies"
             ],
             "fi": [
-                "Jänikset",
-                "Puput"
+                "jänikset",
+                "puput"
             ],
-            "nl": "De konijnen"
+            "nl": "de konijnen"
         }
     },
     "horn": {
@@ -385,14 +405,14 @@
             ]
         },
         "singular": {
-            "en": "Horn",
-            "fi": "Sarvi",
-            "nl": "De hoorn"
+            "en": "horn",
+            "fi": "sarvi",
+            "nl": "de hoorn"
         },
         "plural": {
-            "en": "Horns",
-            "fi": "Sarvet",
-            "nl": "De hoorns"
+            "en": "horns",
+            "fi": "sarvet",
+            "nl": "de hoorns"
         }
     },
     "tail": {
@@ -401,14 +421,14 @@
             "B2": "EP"
         },
         "singular": {
-            "en": "Tail",
-            "fi": "Häntä",
-            "nl": "De staart"
+            "en": "tail",
+            "fi": "häntä",
+            "nl": "de staart"
         },
         "plural": {
             "en": "Tails",
-            "fi": "Hännät",
-            "nl": "De staarten"
+            "fi": "hännät",
+            "nl": "de staarten"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/body.json b/src/topics/body.json
index fbc4868a..6b739b7e 100644
--- a/src/topics/body.json
+++ b/src/topics/body.json
@@ -7,20 +7,20 @@
             ]
         },
         "singular": {
-            "en": "Body",
+            "en": "body",
             "fi": [
-                "Vartalo",
-                "Keho"
+                "vartalo",
+                "keho"
             ],
-            "nl": "Het lichaam"
+            "nl": "het lichaam"
         },
         "plural": {
-            "en": "Bodies",
+            "en": "bodies",
             "fi": [
-                "Vartalot",
-                "Kehot"
+                "vartalot",
+                "kehot"
             ],
-            "nl": "De lichamen"
+            "nl": "de lichamen"
         }
     },
     "eye": {
@@ -32,14 +32,14 @@
             ]
         },
         "singular": {
-            "en": "Eye",
-            "fi": "Silmä",
-            "nl": "Het oog"
+            "en": "eye",
+            "fi": "silmä",
+            "nl": "het oog"
         },
         "plural": {
-            "en": "Eyes",
-            "fi": "Silmät",
-            "nl": "De ogen"
+            "en": "eyes",
+            "fi": "silmät",
+            "nl": "de ogen"
         }
     },
     "ear": {
@@ -51,14 +51,14 @@
             ]
         },
         "singular": {
-            "en": "Ear",
-            "fi": "Korva",
-            "nl": "Het oor"
+            "en": "ear",
+            "fi": "korva",
+            "nl": "het oor"
         },
         "plural": {
-            "en": "Ears",
-            "fi": "Korvat",
-            "nl": "De oren"
+            "en": "ears",
+            "fi": "korvat",
+            "nl": "de oren"
         }
     },
     "hair": {
@@ -69,17 +69,17 @@
             ]
         },
         "singular": {
-            "en": "Hair",
-            "fi": "Hius",
+            "en": "hair",
+            "fi": "hius",
             "nl": [
-                "De haar",
-                "Het haar"
+                "de haar",
+                "het haar"
             ]
         },
         "plural": {
-            "en": "Hairs",
-            "fi": "Hiukset",
-            "nl": "De haren"
+            "en": "hairs",
+            "fi": "hiukset",
+            "nl": "de haren"
         }
     },
     "nose": {
@@ -90,14 +90,14 @@
             ]
         },
         "singular": {
-            "en": "Nose",
-            "fi": "Nenä",
-            "nl": "De neus"
+            "en": "nose",
+            "fi": "nenä",
+            "nl": "de neus"
         },
         "plural": {
-            "en": "Noses",
-            "fi": "Nenät",
-            "nl": "De neuzen"
+            "en": "noses",
+            "fi": "nenät",
+            "nl": "de neuzen"
         }
     },
     "mouth": {
@@ -108,14 +108,14 @@
             ]
         },
         "singular": {
-            "en": "Mouth",
-            "fi": "Suu",
-            "nl": "De mond"
+            "en": "mouth",
+            "fi": "suu",
+            "nl": "de mond"
         },
         "plural": {
-            "en": "Mouths",
-            "fi": "Suut",
-            "nl": "De monden"
+            "en": "mouths",
+            "fi": "suut",
+            "nl": "de monden"
         }
     },
     "lip": {
@@ -126,14 +126,14 @@
             ]
         },
         "singular": {
-            "en": "Lip",
-            "fi": "Huuli",
-            "nl": "De lip"
+            "en": "lip",
+            "fi": "huuli",
+            "nl": "de lip"
         },
         "plural": {
-            "en": "Lips",
-            "fi": "Huulet",
-            "nl": "De lippen"
+            "en": "lips",
+            "fi": "huulet",
+            "nl": "de lippen"
         }
     },
     "tooth": {
@@ -144,14 +144,14 @@
             ]
         },
         "singular": {
-            "en": "Tooth",
-            "fi": "Hammas",
-            "nl": "De tand"
+            "en": "tooth",
+            "fi": "hammas",
+            "nl": "de tand"
         },
         "plural": {
-            "en": "Teeth",
-            "fi": "Hampaat",
-            "nl": "De tanden"
+            "en": "teeth",
+            "fi": "hampaat",
+            "nl": "de tanden"
         }
     },
     "head": {
@@ -163,14 +163,14 @@
             ]
         },
         "singular": {
-            "en": "Head",
-            "fi": "Pää",
-            "nl": "Het hoofd"
+            "en": "head",
+            "fi": "pää",
+            "nl": "het hoofd"
         },
         "plural": {
-            "en": "Heads",
-            "fi": "Päät",
-            "nl": "De hoofden"
+            "en": "heads",
+            "fi": "päät",
+            "nl": "de hoofden"
         }
     },
     "back": {
@@ -179,14 +179,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Back",
-            "fi": "Selkä",
-            "nl": "De rug"
+            "en": "back",
+            "fi": "selkä",
+            "nl": "de rug"
         },
         "plural": {
-            "en": "Backs",
-            "fi": "Selät",
-            "nl": "De ruggen"
+            "en": "backs",
+            "fi": "selät",
+            "nl": "de ruggen"
         }
     },
     "shoulder": {
@@ -198,14 +198,14 @@
             "fi": "head"
         },
         "singular": {
-            "en": "Shoulder",
-            "fi": "Olkapää",
-            "nl": "De schouder"
+            "en": "shoulder",
+            "fi": "olkapää",
+            "nl": "de schouder"
         },
         "plural": {
-            "en": "Shoulders",
-            "fi": "Olkapäät",
-            "nl": "De schouders"
+            "en": "shoulders",
+            "fi": "olkapäät",
+            "nl": "de schouders"
         }
     },
     "arm": {
@@ -219,14 +219,14 @@
             "fi": "hand"
         },
         "singular": {
-            "en": "Arm",
-            "fi": "Käsivarsi",
-            "nl": "De arm"
+            "en": "arm",
+            "fi": "käsivarsi",
+            "nl": "de arm"
         },
         "plural": {
-            "en": "Arms",
-            "fi": "Käsivarret",
-            "nl": "De armen"
+            "en": "arms",
+            "fi": "käsivarret",
+            "nl": "de armen"
         }
     },
     "hand": {
@@ -238,14 +238,14 @@
             ]
         },
         "singular": {
-            "en": "Hand",
-            "fi": "Käsi",
-            "nl": "De hand"
+            "en": "hand",
+            "fi": "käsi",
+            "nl": "de hand"
         },
         "plural": {
-            "en": "Hands",
-            "fi": "Kädet",
-            "nl": "De handen"
+            "en": "hands",
+            "fi": "kädet",
+            "nl": "de handen"
         }
     },
     "finger": {
@@ -257,14 +257,14 @@
             ]
         },
         "singular": {
-            "en": "Finger",
-            "fi": "Sormi",
-            "nl": "De vinger"
+            "en": "finger",
+            "fi": "sormi",
+            "nl": "de vinger"
         },
         "plural": {
-            "en": "Fingers",
-            "fi": "Sormet",
-            "nl": "De vingers"
+            "en": "fingers",
+            "fi": "sormet",
+            "nl": "de vingers"
         }
     },
     "stomach": {
@@ -275,14 +275,14 @@
             ]
         },
         "singular": {
-            "en": "Stomach",
-            "fi": "Vatsa",
-            "nl": "De maag"
+            "en": "stomach",
+            "fi": "vatsa",
+            "nl": "de maag"
         },
         "plural": {
-            "en": "Stomachs",
-            "fi": "Vatsat",
-            "nl": "De magen"
+            "en": "stomachs",
+            "fi": "vatsat",
+            "nl": "de magen"
         }
     },
     "belly": {
@@ -291,20 +291,20 @@
             "none": "EP"
         },
         "singular": {
-            "en": "Belly",
+            "en": "belly",
             "fi": [
-                "Maha",
-                "Masu"
+                "maha",
+                "masu"
             ],
-            "nl": "De buik"
+            "nl": "de buik"
         },
         "plural": {
-            "en": "Bellies",
+            "en": "bellies",
             "fi": [
-                "Mahat",
-                "Masut"
+                "mahat",
+                "masut"
             ],
-            "nl": "De buiken"
+            "nl": "de buiken"
         }
     },
     "knee": {
@@ -313,14 +313,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Knee",
-            "fi": "Polvi",
-            "nl": "De knie"
+            "en": "knee",
+            "fi": "polvi",
+            "nl": "de knie"
         },
         "plural": {
-            "en": "Knees",
-            "fi": "Polvet",
-            "nl": "De knieën"
+            "en": "knees",
+            "fi": "polvet",
+            "nl": "de knieën"
         }
     },
     "leg": {
@@ -332,14 +332,14 @@
             ]
         },
         "singular": {
-            "en": "Leg",
-            "fi": "Jalka;upper part",
-            "nl": "Het been"
+            "en": "leg",
+            "fi": "jalka;upper part",
+            "nl": "het been"
         },
         "plural": {
-            "en": "Legs",
-            "fi": "Jalat;upper part",
-            "nl": "De benen"
+            "en": "legs",
+            "fi": "jalat;upper part",
+            "nl": "de benen"
         }
     },
     "foot": {
@@ -351,14 +351,14 @@
             ]
         },
         "singular": {
-            "en": "Foot",
-            "fi": "Jalka;lower part",
-            "nl": "De voet"
+            "en": "foot",
+            "fi": "jalka;lower part",
+            "nl": "de voet"
         },
         "plural": {
-            "en": "Feet",
-            "fi": "Jalat;lower part",
-            "nl": "De voeten"
+            "en": "feet",
+            "fi": "jalat;lower part",
+            "nl": "de voeten"
         }
     },
     "toe": {
@@ -367,14 +367,14 @@
             "B1": "OD"
         },
         "singular": {
-            "en": "Toe",
-            "fi": "Varvas",
-            "nl": "De teen"
+            "en": "toe",
+            "fi": "varvas",
+            "nl": "de teen"
         },
         "plural": {
-            "en": "Toes",
-            "fi": "Varpaat",
-            "nl": "De tenen"
+            "en": "toes",
+            "fi": "varpaat",
+            "nl": "de tenen"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/city.json b/src/topics/city.json
index 4f128b48..f342eae9 100644
--- a/src/topics/city.json
+++ b/src/topics/city.json
@@ -8,14 +8,14 @@
             ]
         },
         "singular": {
-            "en": "City",
-            "fi": "Kaupunki",
-            "nl": "De stad"
+            "en": "city",
+            "fi": "kaupunki",
+            "nl": "de stad"
         },
         "plural": {
-            "en": "Cities",
-            "fi": "Kaupungit",
-            "nl": "De steden"
+            "en": "cities",
+            "fi": "kaupungit",
+            "nl": "de steden"
         }
     },
     "building": {
@@ -27,14 +27,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Building",
-            "fi": "Rakennus",
-            "nl": "Het gebouw"
+            "en": "building",
+            "fi": "rakennus",
+            "nl": "het gebouw"
         },
         "plural": {
-            "en": "Buildings",
-            "fi": "Rakennukset",
-            "nl": "De gebouwen"
+            "en": "buildings",
+            "fi": "rakennukset",
+            "nl": "de gebouwen"
         }
     },
     "monument": {
@@ -43,14 +43,14 @@
             "B2": "OD"
         },
         "singular": {
-            "en": "Monument",
-            "fi": "Monumentti",
-            "nl": "Het monument"
+            "en": "monument",
+            "fi": "monumentti",
+            "nl": "het monument"
         },
         "plural": {
-            "en": "Monuments",
-            "fi": "Monumentit",
-            "nl": "De monumenten"
+            "en": "monuments",
+            "fi": "monumentit",
+            "nl": "de monumenten"
         }
     },
     "theater": {
@@ -59,14 +59,14 @@
             "none": "EP"
         },
         "singular": {
-            "en": "Theater",
-            "fi": "Teatteri",
+            "en": "theater",
+            "fi": "teatteri",
             "nl": "Het theater"
         },
         "plural": {
-            "en": "Theaters",
-            "fi": "Teatterit",
-            "nl": "De theaters"
+            "en": "theaters",
+            "fi": "teatterit",
+            "nl": "de theaters"
         }
     },
     "museum": {
@@ -77,14 +77,14 @@
             ]
         },
         "singular": {
-            "en": "Museum",
-            "fi": "Museo",
-            "nl": "Het museum"
+            "en": "museum",
+            "fi": "museo",
+            "nl": "het museum"
         },
         "plural": {
-            "en": "Museums",
-            "fi": "Museot",
-            "nl": "De musea"
+            "en": "museums",
+            "fi": "museot",
+            "nl": "de musea"
         }
     },
     "church": {
@@ -96,14 +96,14 @@
             ]
         },
         "singular": {
-            "en": "Church",
-            "fi": "Kirkko",
-            "nl": "De kerk"
+            "en": "church",
+            "fi": "kirkko",
+            "nl": "de kerk"
         },
         "plural": {
-            "en": "Churches",
-            "fi": "Kirkot",
-            "nl": "De kerken"
+            "en": "churches",
+            "fi": "kirkot",
+            "nl": "de kerken"
         }
     },
     "stadium": {
@@ -114,14 +114,14 @@
             ]
         },
         "singular": {
-            "en": "Stadium",
-            "fi": "Stadion",
-            "nl": "Het stadion"
+            "en": "stadium",
+            "fi": "stadion",
+            "nl": "het stadion"
         },
         "plural": {
-            "en": "Stadiums",
-            "fi": "Stadionit",
-            "nl": "De stadions"
+            "en": "stadiums",
+            "fi": "stadionit",
+            "nl": "de stadions"
         }
     },
     "library": {
@@ -133,14 +133,14 @@
             "fi": "book"
         },
         "singular": {
-            "en": "Library",
-            "fi": "Kirjasto",
-            "nl": "De bibliotheek"
+            "en": "library",
+            "fi": "kirjasto",
+            "nl": "de bibliotheek"
         },
         "plural": {
-            "en": "Libraries",
-            "fi": "Kirjastot",
-            "nl": "De bibliotheken"
+            "en": "libraries",
+            "fi": "kirjastot",
+            "nl": "de bibliotheken"
         }
     },
     "hospital": {
@@ -155,14 +155,14 @@
             "nl": "house"
         },
         "singular": {
-            "en": "Hospital",
-            "fi": "Sairaala",
-            "nl": "Het ziekenhuis"
+            "en": "hospital",
+            "fi": "sairaala",
+            "nl": "het ziekenhuis"
         },
         "plural": {
-            "en": "Hospitals",
-            "fi": "Sairaalat",
-            "nl": "De ziekenhuizen"
+            "en": "hospitals",
+            "fi": "sairaalat",
+            "nl": "de ziekenhuizen"
         }
     },
     "office": {
@@ -171,14 +171,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Office",
-            "fi": "Toimisto",
-            "nl": "Het kantoor"
+            "en": "office",
+            "fi": "toimisto",
+            "nl": "het kantoor"
         },
         "plural": {
-            "en": "Offices",
-            "fi": "Toimistot",
-            "nl": "De kantoren"
+            "en": "offices",
+            "fi": "toimistot",
+            "nl": "de kantoren"
         }
     },
     "airport": {
@@ -190,14 +190,14 @@
             "en": "port"
         },
         "singular": {
-            "en": "Airport",
-            "fi": "Lentokenttä",
-            "nl": "Het vliegveld"
+            "en": "airport",
+            "fi": "lentokenttä",
+            "nl": "het vliegveld"
         },
         "plural": {
-            "en": "Airports",
-            "fi": "Lentokentät",
-            "nl": "De vliegvelden"
+            "en": "airports",
+            "fi": "lentokentät",
+            "nl": "de vliegvelden"
         }
     },
     "store": {
@@ -207,14 +207,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Store",
-            "fi": "Kauppa",
-            "nl": "De winkel"
+            "en": "store",
+            "fi": "kauppa",
+            "nl": "de winkel"
         },
         "plural": {
-            "en": "Stores",
-            "fi": "Kaupat",
-            "nl": "De winkels"
+            "en": "stores",
+            "fi": "kaupat",
+            "nl": "de winkels"
         }
     },
     "department store": {
@@ -228,14 +228,14 @@
             "nl": "house"
         },
         "singular": {
-            "en": "Department store",
-            "fi": "Tavaratalo",
-            "nl": "Het warenhuis"
+            "en": "department store",
+            "fi": "tavaratalo",
+            "nl": "het warenhuis"
         },
         "plural": {
-            "en": "Department stores",
-            "fi": "Tavaratalot",
-            "nl": "De warenhuizen"
+            "en": "department stores",
+            "fi": "tavaratalot",
+            "nl": "de warenhuizen"
         }
     },
     "park": {
@@ -246,14 +246,14 @@
             ]
         },
         "singular": {
-            "en": "Park",
-            "fi": "Puisto",
-            "nl": "Het park"
+            "en": "park",
+            "fi": "puisto",
+            "nl": "het park"
         },
         "plural": {
-            "en": "Parks",
-            "fi": "Puistot",
-            "nl": "De parken"
+            "en": "parks",
+            "fi": "puistot",
+            "nl": "de parken"
         }
     },
     "castle": {
@@ -264,14 +264,14 @@
             ]
         },
         "singular": {
-            "en": "Castle",
-            "fi": "Linna",
-            "nl": "Het kasteel"
+            "en": "castle",
+            "fi": "linna",
+            "nl": "het kasteel"
         },
         "plural": {
-            "en": "Castles",
-            "fi": "Linnat",
-            "nl": "De kastelen"
+            "en": "castles",
+            "fi": "linnat",
+            "nl": "de kastelen"
         }
     },
     "hotel": {
@@ -282,14 +282,14 @@
             ]
         },
         "singular": {
-            "en": "Hotel",
-            "fi": "Hotelli",
-            "nl": "Het hotel"
+            "en": "hotel",
+            "fi": "hotelli",
+            "nl": "het hotel"
         },
         "plural": {
-            "en": "Hotels",
-            "fi": "Hotellit",
-            "nl": "De hotels"
+            "en": "hotels",
+            "fi": "hotellit",
+            "nl": "de hotels"
         }
     },
     "centre": {
@@ -301,14 +301,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Centre",
-            "fi": "Keskusta",
-            "nl": "Het centrum"
+            "en": "centre",
+            "fi": "keskusta",
+            "nl": "het centrum"
         },
         "plural": {
-            "en": "Centres",
-            "fi": "Keskustat",
-            "nl": "De centra"
+            "en": "centres",
+            "fi": "keskustat",
+            "nl": "de centra"
         }
     },
     "street": {
@@ -320,14 +320,14 @@
             ]
         },
         "singular": {
-            "en": "Street",
-            "fi": "Katu",
-            "nl": "De straat"
+            "en": "street",
+            "fi": "katu",
+            "nl": "de straat"
         },
         "plural": {
-            "en": "Streets",
-            "fi": "Kadut",
-            "nl": "De straten"
+            "en": "streets",
+            "fi": "kadut",
+            "nl": "de straten"
         }
     },
     "square": {
@@ -338,14 +338,14 @@
             ]
         },
         "singular": {
-            "en": "Square",
-            "fi": "Aukio",
-            "nl": "Het plein"
+            "en": "square",
+            "fi": "aukio",
+            "nl": "het plein"
         },
         "plural": {
-            "en": "Squares",
-            "fi": "Aukiot",
-            "nl": "De pleinen"
+            "en": "squares",
+            "fi": "aukiot",
+            "nl": "de pleinen"
         }
     },
     "bridge": {
@@ -356,14 +356,14 @@
             ]
         },
         "singular": {
-            "en": "Bridge",
-            "fi": "Silta",
-            "nl": "De brug"
+            "en": "bridge",
+            "fi": "silta",
+            "nl": "de brug"
         },
         "plural": {
-            "en": "Bridges",
-            "fi": "Sillat",
-            "nl": "De bruggen"
+            "en": "bridges",
+            "fi": "sillat",
+            "nl": "de bruggen"
         }
     },
     "port": {
@@ -374,14 +374,14 @@
             ]
         },
         "singular": {
-            "en": "Port",
-            "fi": "Satama",
-            "nl": "De haven"
+            "en": "port",
+            "fi": "satama",
+            "nl": "de haven"
         },
         "plural": {
-            "en": "Ports",
-            "fi": "Satamat",
-            "nl": "De havens"
+            "en": "ports",
+            "fi": "satamat",
+            "nl": "de havens"
         }
     },
     "mall": {
@@ -404,25 +404,25 @@
         },
         "singular": {
             "en": [
-                "Mall",
-                "Shopping center"
+                "mall",
+                "shopping center"
             ],
             "fi": [
-                "Kauppakeskus",
-                "Ostoskeskus"
+                "kauppakeskus",
+                "ostoskeskus"
             ],
             "nl": "Het winkelcentrum"
         },
         "plural": {
             "en": [
-                "Malls",
-                "Shopping centers"
+                "malls",
+                "shopping centers"
             ],
             "fi": [
-                "Kauppakeskukset",
-                "Ostoskeskukset"
+                "kauppakeskukset",
+                "ostoskeskukset"
             ],
-            "nl": "De winkelcentra"
+            "nl": "de winkelcentra"
         }
     },
     "capital": {
@@ -441,14 +441,14 @@
             ]
         },
         "singular": {
-            "en": "Capital",
-            "fi": "Pääkaupunki",
-            "nl": "De hoofdstad"
+            "en": "capital",
+            "fi": "pääkaupunki",
+            "nl": "de hoofdstad"
         },
         "plural": {
-            "en": "Capitals",
-            "fi": "Pääkaupungit",
-            "nl": "De hoofdsteden"
+            "en": "capitals",
+            "fi": "pääkaupungit",
+            "nl": "de hoofdsteden"
         }
     },
     "that building is a church": {
diff --git a/src/topics/clothes.json b/src/topics/clothes.json
index c6291724..0daa1c42 100644
--- a/src/topics/clothes.json
+++ b/src/topics/clothes.json
@@ -6,9 +6,9 @@
                 "OD"
             ]
         },
-        "en": "Clothes",
-        "fi": "Vaatteet",
-        "nl": "De kleren"
+        "en": "clothes",
+        "fi": "vaatteet",
+        "nl": "de kleren"
     },
     "dress": {
         "level": {
@@ -18,14 +18,14 @@
             ]
         },
         "singular": {
-            "en": "Dress",
-            "fi": "Mekko",
-            "nl": "De jurk"
+            "en": "dress",
+            "fi": "mekko",
+            "nl": "de jurk"
         },
         "plural": {
-            "en": "Dresses",
-            "fi": "Mekot",
-            "nl": "De jurken"
+            "en": "dresses",
+            "fi": "mekot",
+            "nl": "de jurken"
         }
     },
     "sock": {
@@ -36,14 +36,14 @@
             ]
         },
         "singular": {
-            "en": "Sock",
-            "fi": "Sukka",
-            "nl": "De sok"
+            "en": "sock",
+            "fi": "sukka",
+            "nl": "de sok"
         },
         "plural": {
-            "en": "Socks",
-            "fi": "Sukat",
-            "nl": "De sokken"
+            "en": "socks",
+            "fi": "sukat",
+            "nl": "de sokken"
         }
     },
     "skirt": {
@@ -54,14 +54,14 @@
             ]
         },
         "singular": {
-            "en": "Skirt",
-            "fi": "Hame",
-            "nl": "De rok"
+            "en": "skirt",
+            "fi": "hame",
+            "nl": "de rok"
         },
         "plural": {
-            "en": "Skirts",
-            "fi": "Hameet",
-            "nl": "De rokken"
+            "en": "skirts",
+            "fi": "hameet",
+            "nl": "de rokken"
         }
     },
     "trousers": {
@@ -72,12 +72,14 @@
             ]
         },
         "singular": {
-            "en": "Trousers",
-            "fi": "Housut",
-            "nl": "De broek"
+            "en": "trousers",
+            "fi": "housut",
+            "nl": "de broek"
         },
         "plural": {
-            "nl": "De broeken"
+            "en": "(pairs of trousers)",
+            "nl": "de broeken",
+            "fi": "(paria housut)"
         }
     },
     "coat": {
@@ -88,14 +90,14 @@
             ]
         },
         "singular": {
-            "en": "Coat",
-            "fi": "Takki",
-            "nl": "De jas"
+            "en": "coat",
+            "fi": "takki",
+            "nl": "de jas"
         },
         "plural": {
-            "en": "Coats",
-            "fi": "Takit",
-            "nl": "De jassen"
+            "en": "coats",
+            "fi": "takit",
+            "nl": "de jassen"
         }
     },
     "underwear": {
@@ -108,9 +110,9 @@
         "roots": {
             "fi": "clothes"
         },
-        "en": "Underwear",
-        "fi": "Alusvaatteet",
-        "nl": "Het ondergoed"
+        "en": "underwear",
+        "fi": "alusvaatteet",
+        "nl": "het ondergoed"
     },
     "hat": {
         "level": {
@@ -120,14 +122,14 @@
             ]
         },
         "singular": {
-            "en": "Hat",
-            "fi": "Hattu",
-            "nl": "De hoed"
+            "en": "hat",
+            "fi": "hattu",
+            "nl": "de hoed"
         },
         "plural": {
-            "en": "Hats",
-            "fi": "Hatut",
-            "nl": "De hoeden"
+            "en": "hats",
+            "fi": "hatut",
+            "nl": "de hoeden"
         }
     },
     "suit": {
@@ -138,14 +140,14 @@
             ]
         },
         "singular": {
-            "en": "Suit",
-            "fi": "Puku",
-            "nl": "Het pak"
+            "en": "suit",
+            "fi": "puku",
+            "nl": "het pak"
         },
         "plural": {
-            "en": "Suits",
-            "fi": "Puvut",
-            "nl": "De pakken"
+            "en": "suits",
+            "fi": "puvut",
+            "nl": "de pakken"
         }
     },
     "shoe": {
@@ -156,14 +158,14 @@
             ]
         },
         "singular": {
-            "en": "Shoe",
-            "fi": "Kenkä",
-            "nl": "De schoen"
+            "en": "shoe",
+            "fi": "kenkä",
+            "nl": "de schoen"
         },
         "plural": {
-            "en": "Shoes",
-            "fi": "Kengät",
-            "nl": "De schoenen"
+            "en": "shoes",
+            "fi": "kengät",
+            "nl": "de schoenen"
         }
     },
     "sweater": {
@@ -175,14 +177,14 @@
             "fi": "shirt"
         },
         "singular": {
-            "en": "Sweater",
-            "fi": "Neulepaita",
-            "nl": "De trui"
+            "en": "sweater",
+            "fi": "neulepaita",
+            "nl": "de trui"
         },
         "plural": {
-            "en": "Sweaters",
-            "fi": "Neulepaidat",
-            "nl": "De truien"
+            "en": "sweaters",
+            "fi": "neulepaidat",
+            "nl": "de truien"
         }
     },
     "shirt": {
@@ -193,14 +195,14 @@
             ]
         },
         "singular": {
-            "en": "Shirt",
-            "fi": "Paita",
-            "nl": "Het hemd"
+            "en": "shirt",
+            "fi": "paita",
+            "nl": "het hemd"
         },
         "plural": {
-            "en": "Shirts",
-            "fi": "Paidat",
-            "nl": "De hemden"
+            "en": "shirts",
+            "fi": "paidat",
+            "nl": "de hemden"
         }
     },
     "to dress": {
@@ -210,11 +212,11 @@
         },
         "infinitive": {
             "en": [
-                "To dress",
-                "To get dressed"
+                "to dress",
+                "to get dressed"
             ],
-            "fi": "Pukeutua",
-            "nl": "Zich aankleden"
+            "fi": "pukeutua",
+            "nl": "zich aankleden"
         },
         "singular": {
             "first person": {
@@ -222,60 +224,60 @@
                     "I dress",
                     "I get dressed"
                 ],
-                "fi": "Minä pukeudun|Pukeudun",
-                "nl": "Ik kleed mij aan|Ik kleed me aan"
+                "fi": "minä pukeudun|pukeudun",
+                "nl": "ik kleed mij aan|ik kleed me aan"
             },
             "second person": {
                 "en": [
-                    "You dress;singular",
-                    "You get dressed;singular"
+                    "you dress;singular",
+                    "you get dressed;singular"
                 ],
-                "fi": "Sinä pukeudut|Pukeudut",
-                "nl": "Jij kleedt je aan"
+                "fi": "sinä pukeudut|pukeudut",
+                "nl": "jij kleedt je aan"
             },
             "third person": {
                 "female": {
                     "en": [
-                        "She dresses",
-                        "She gets dressed"
+                        "she dresses",
+                        "she gets dressed"
                     ],
-                    "fi": "Hän pukeutuu;female",
-                    "nl": "Zij kleedt zich aan|Ze kleedt zich aan"
+                    "fi": "hän pukeutuu;female",
+                    "nl": "zij kleedt zich aan|ze kleedt zich aan"
                 },
                 "male": {
                     "en": [
-                        "He dresses",
-                        "He gets dressed"
+                        "he dresses",
+                        "he gets dressed"
                     ],
-                    "fi": "Hän pukeutuu;male",
-                    "nl": "Hij kleedt zich aan"
+                    "fi": "hän pukeutuu;male",
+                    "nl": "hij kleedt zich aan"
                 }
             }
         },
         "plural": {
             "first person": {
                 "en": [
-                    "We dress",
-                    "We get dressed"
+                    "we dress",
+                    "we get dressed"
                 ],
-                "fi": "Me pukeudumme|Pukeudumme",
-                "nl": "Wij kleden ons aan|We kleden ons aan"
+                "fi": "me pukeudumme|pukeudumme",
+                "nl": "wij kleden ons aan|we kleden ons aan"
             },
             "second person": {
                 "en": [
-                    "You dress;plural",
-                    "You get dressed;plural"
+                    "you dress;plural",
+                    "you get dressed;plural"
                 ],
-                "fi": "Te pukeudutte|Pukeudutte",
-                "nl": "Jullie kleden je aan"
+                "fi": "te pukeudutte|pukeudutte",
+                "nl": "jullie kleden je aan"
             },
             "third person": {
                 "en": [
-                    "They dress",
-                    "They get dressed"
+                    "they dress",
+                    "they get dressed"
                 ],
-                "fi": "He pukeutuvat|Pukeutuvat",
-                "nl": "Zij kleden zich aan|Ze kleden zich aan"
+                "fi": "he pukeutuvat|pukeutuvat",
+                "nl": "zij kleden zich aan|ze kleden zich aan"
             }
         }
     }
diff --git a/src/topics/colors.json b/src/topics/colors.json
index 52369726..f0a786b4 100644
--- a/src/topics/colors.json
+++ b/src/topics/colors.json
@@ -8,9 +8,9 @@
                 "OD"
             ]
         },
-        "en": "Black",
-        "fi": "Musta",
-        "nl": "Zwart"
+        "en": "black",
+        "fi": "musta",
+        "nl": "zwart"
     },
     "white": {
         "antonym": "black",
@@ -21,9 +21,9 @@
                 "OD"
             ]
         },
-        "en": "White",
-        "fi": "Valkoinen",
-        "nl": "Wit"
+        "en": "white",
+        "fi": "valkoinen",
+        "nl": "wit"
     },
     "blue": {
         "level": {
@@ -32,9 +32,9 @@
                 "OD"
             ]
         },
-        "en": "Blue",
-        "fi": "Sininen",
-        "nl": "Blauw"
+        "en": "blue",
+        "fi": "sininen",
+        "nl": "blauw"
     },
     "green": {
         "level": {
@@ -44,9 +44,9 @@
                 "OD"
             ]
         },
-        "en": "Green",
-        "fi": "Vihreä",
-        "nl": "Groen"
+        "en": "green",
+        "fi": "vihreä",
+        "nl": "groen"
     },
     "red": {
         "level": {
@@ -56,9 +56,9 @@
                 "OD"
             ]
         },
-        "en": "Red",
-        "fi": "Punainen",
-        "nl": "Rood"
+        "en": "red",
+        "fi": "punainen",
+        "nl": "rood"
     },
     "yellow": {
         "level": {
@@ -67,21 +67,21 @@
                 "OD"
             ]
         },
-        "en": "Yellow",
-        "fi": "Keltainen",
-        "nl": "Geel"
+        "en": "yellow",
+        "fi": "keltainen",
+        "nl": "geel"
     },
     "purple": {
         "level": {
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "Purple",
+        "en": "purple",
         "fi": [
-            "Liila",
-            "Violetti"
+            "liila",
+            "violetti"
         ],
-        "nl": "Paars"
+        "nl": "paars"
     },
     "orange": {
         "level": {
@@ -90,9 +90,9 @@
                 "OD"
             ]
         },
-        "en": "Orange",
-        "fi": "Oranssi",
-        "nl": "Oranje"
+        "en": "orange",
+        "fi": "oranssi",
+        "nl": "oranje"
     },
     "brown": {
         "level": {
@@ -101,21 +101,21 @@
                 "OD"
             ]
         },
-        "en": "Brown",
-        "fi": "Ruskea",
-        "nl": "Bruin"
+        "en": "brown",
+        "fi": "ruskea",
+        "nl": "bruin"
     },
     "pink": {
         "level": {
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "Pink",
+        "en": "pink",
         "fi": [
-            "Vaaleanpunainen",
-            "Pinkki"
+            "vaaleanpunainen",
+            "pinkki"
         ],
-        "nl": "Roze"
+        "nl": "roze"
     },
     "grey": {
         "level": {
@@ -124,9 +124,9 @@
                 "OD"
             ]
         },
-        "en": "Grey|Gray",
-        "fi": "Harmaa",
-        "nl": "Grijs"
+        "en": "grey|gray",
+        "fi": "harmaa",
+        "nl": "grijs"
     },
     "light blue": {
         "level": {
@@ -134,9 +134,9 @@
             "A2": "EP"
         },
         "roots": "blue",
-        "en": "Light blue",
-        "fi": "Vaaleansininen",
-        "nl": "Lichtblauw"
+        "en": "light blue",
+        "fi": "vaaleansininen",
+        "nl": "lichtblauw"
     },
     "dark blue": {
         "level": {
@@ -144,8 +144,8 @@
             "A2": "EP"
         },
         "roots": "blue",
-        "en": "Dark blue",
-        "fi": "Tummansininen",
+        "en": "dark blue",
+        "fi": "tummansininen",
         "nl": "Donkerblauw"
     },
     "the car is blue": {
@@ -264,7 +264,7 @@
         },
         "plural": {
             "en": "I read the red books;present tense",
-            "fi": "Minä luen punaisia ​​kirjoj|Luen punaisia ​​kirjoja",
+            "fi": "Minä luen punaisia kirjoja|Luen punaisia kirjoja",
             "nl": "Ik lees de rode boeken"
         }
     },
diff --git a/src/topics/counting.json b/src/topics/counting.json
index d7a25ab6..f9ff3716 100644
--- a/src/topics/counting.json
+++ b/src/topics/counting.json
@@ -5,9 +5,9 @@
             "A2": "OD",
             "B1": "EP"
         },
-        "en": "To count",
-        "fi": "Laskea",
-        "nl": "Tellen"
+        "en": "to count",
+        "fi": "laskea",
+        "nl": "tellen"
     },
     "1": {
         "level": {
@@ -17,9 +17,9 @@
                 "OD"
             ]
         },
-        "en": "One",
-        "fi": "Yksi",
-        "nl": "Eén|één|Een"
+        "en": "one",
+        "fi": "yksi",
+        "nl": "één|een"
     },
     "2": {
         "level": {
@@ -29,9 +29,9 @@
                 "OD"
             ]
         },
-        "en": "Two",
-        "fi": "Kaksi",
-        "nl": "Twee"
+        "en": "two",
+        "fi": "kaksi",
+        "nl": "twee"
     },
     "3": {
         "level": {
@@ -41,9 +41,9 @@
                 "OD"
             ]
         },
-        "en": "Three",
-        "fi": "Kolme",
-        "nl": "Drie"
+        "en": "three",
+        "fi": "kolme",
+        "nl": "drie"
     },
     "4": {
         "level": {
@@ -53,9 +53,9 @@
                 "OD"
             ]
         },
-        "en": "Four",
-        "fi": "Neljä",
-        "nl": "Vier"
+        "en": "four",
+        "fi": "neljä",
+        "nl": "vier"
     },
     "5": {
         "level": {
@@ -65,9 +65,9 @@
                 "OD"
             ]
         },
-        "en": "Five",
-        "fi": "Viisi",
-        "nl": "Vijf"
+        "en": "five",
+        "fi": "viisi",
+        "nl": "vijf"
     },
     "6": {
         "level": {
@@ -77,9 +77,9 @@
                 "OD"
             ]
         },
-        "en": "Six",
-        "fi": "Kuusi",
-        "nl": "Zes"
+        "en": "six",
+        "fi": "kuusi",
+        "nl": "zes"
     },
     "7": {
         "level": {
@@ -88,9 +88,9 @@
                 "OD"
             ]
         },
-        "en": "Seven",
-        "fi": "Seitsemän",
-        "nl": "Zeven"
+        "en": "seven",
+        "fi": "seitsemän",
+        "nl": "zeven"
     },
     "8": {
         "level": {
@@ -99,9 +99,9 @@
                 "OD"
             ]
         },
-        "en": "Eight",
-        "fi": "Kahdeksan",
-        "nl": "Acht"
+        "en": "eight",
+        "fi": "kahdeksan",
+        "nl": "acht"
     },
     "9": {
         "level": {
@@ -110,9 +110,9 @@
                 "OD"
             ]
         },
-        "en": "Nine",
-        "nl": "Negen",
-        "fi": "Yhdeksän"
+        "en": "nine",
+        "nl": "negen",
+        "fi": "yhdeksän"
     },
     "10": {
         "level": {
@@ -122,9 +122,9 @@
                 "OD"
             ]
         },
-        "en": "Ten",
-        "fi": "Kymmenen",
-        "nl": "Tien"
+        "en": "ten",
+        "fi": "kymmenen",
+        "nl": "tien"
     },
     "11": {
         "level": {
@@ -137,9 +137,9 @@
             "1",
             "10"
         ],
-        "en": "Eleven",
-        "fi": "Yksitoista",
-        "nl": "Elf"
+        "en": "eleven",
+        "fi": "yksitoista",
+        "nl": "elf"
     },
     "12": {
         "level": {
@@ -152,9 +152,9 @@
             "2",
             "10"
         ],
-        "en": "Twelve",
-        "fi": "Kaksitoista",
-        "nl": "Twaalf"
+        "en": "twelve",
+        "fi": "kaksitoista",
+        "nl": "twaalf"
     },
     "13": {
         "level": {
@@ -167,9 +167,9 @@
             "3",
             "10"
         ],
-        "en": "Thirteen",
-        "fi": "Kolmetoista",
-        "nl": "Dertien"
+        "en": "thirteen",
+        "fi": "kolmetoista",
+        "nl": "dertien"
     },
     "14": {
         "level": {
@@ -182,9 +182,9 @@
             "4",
             "10"
         ],
-        "en": "Fourteen",
-        "fi": "Neljätoista",
-        "nl": "Veertien"
+        "en": "fourteen",
+        "fi": "neljätoista",
+        "nl": "veertien"
     },
     "15": {
         "level": {
@@ -197,9 +197,9 @@
             "5",
             "10"
         ],
-        "en": "Fifteen",
-        "fi": "Viisitoista",
-        "nl": "Vijftien"
+        "en": "fifteen",
+        "fi": "viisitoista",
+        "nl": "vijftien"
     },
     "16": {
         "level": {
@@ -212,8 +212,8 @@
             "6",
             "10"
         ],
-        "en": "Sixteen",
-        "fi": "Kuusitoista",
+        "en": "sixteen",
+        "fi": "kuusitoista",
         "nl": "Zestien"
     },
     "17": {
@@ -227,9 +227,9 @@
             "7",
             "10"
         ],
-        "en": "Seventeen",
-        "fi": "Seitsemäntoista",
-        "nl": "Zeventien"
+        "en": "seventeen",
+        "fi": "seitsemäntoista",
+        "nl": "zeventien"
     },
     "18": {
         "level": {
@@ -242,9 +242,9 @@
             "8",
             "10"
         ],
-        "en": "Eightteen",
-        "fi": "Kahdeksantoista",
-        "nl": "Achttien"
+        "en": "eightteen",
+        "fi": "kahdeksantoista",
+        "nl": "achttien"
     },
     "19": {
         "level": {
@@ -257,9 +257,9 @@
             "9",
             "10"
         ],
-        "en": "Nineteen",
-        "fi": "Yhdeksäntoista",
-        "nl": "Negentien"
+        "en": "nineteen",
+        "fi": "yhdeksäntoista",
+        "nl": "negentien"
     },
     "20": {
         "level": {
@@ -272,9 +272,9 @@
             "2",
             "10"
         ],
-        "en": "Twenty",
-        "fi": "Kaksikymmentä",
-        "nl": "Twintig"
+        "en": "twenty",
+        "fi": "kaksikymmentä",
+        "nl": "twintig"
     },
     "21": {
         "level": {
@@ -287,9 +287,9 @@
             "1",
             "20"
         ],
-        "en": "Twenty-one",
-        "fi": "Kaksikymmentäyksi",
-        "nl": "Eenentwintig"
+        "en": "twenty-one",
+        "fi": "kaksikymmentäyksi",
+        "nl": "eenentwintig"
     },
     "22": {
         "level": {
@@ -302,9 +302,9 @@
             "2",
             "20"
         ],
-        "en": "Twenty-two",
-        "fi": "Kaksikymmentäkaksi",
-        "nl": "Tweeëntwintig"
+        "en": "twenty-two",
+        "fi": "kaksikymmentäkaksi",
+        "nl": "tweeëntwintig"
     },
     "23": {
         "level": {
@@ -317,9 +317,9 @@
             "3",
             "20"
         ],
-        "en": "Twenty-three",
-        "fi": "Kaksikymmentäkolme",
-        "nl": "Drieëntwintig"
+        "en": "twenty-three",
+        "fi": "kaksikymmentäkolme",
+        "nl": "drieëntwintig"
     },
     "24": {
         "level": {
@@ -332,9 +332,9 @@
             "4",
             "20"
         ],
-        "en": "Twenty-four",
-        "fi": "Kaksikymmentäneljä",
-        "nl": "Vierentwintig"
+        "en": "twenty-four",
+        "fi": "kaksikymmentäneljä",
+        "nl": "vierentwintig"
     },
     "30": {
         "level": {
@@ -345,9 +345,9 @@
             "3",
             "10"
         ],
-        "en": "Thirty",
-        "fi": "Kolmekymmentä",
-        "nl": "Dertig"
+        "en": "thirty",
+        "fi": "kolmekymmentä",
+        "nl": "dertig"
     },
     "40": {
         "level": {
@@ -358,9 +358,9 @@
             "4",
             "10"
         ],
-        "en": "Forty",
-        "fi": "Neljäkymmentä",
-        "nl": "Veertig"
+        "en": "forty",
+        "fi": "neljäkymmentä",
+        "nl": "veertig"
     },
     "50": {
         "level": {
@@ -371,9 +371,9 @@
             "5",
             "10"
         ],
-        "en": "Fifty",
-        "fi": "Viisikymmentä",
-        "nl": "Vijftig"
+        "en": "fifty",
+        "fi": "viisikymmentä",
+        "nl": "vijftig"
     },
     "60": {
         "level": {
@@ -384,9 +384,9 @@
             "6",
             "10"
         ],
-        "en": "Sixty",
-        "fi": "Kuusikymmentä",
-        "nl": "Zestig"
+        "en": "sixty",
+        "fi": "kuusikymmentä",
+        "nl": "zestig"
     },
     "70": {
         "level": {
@@ -397,9 +397,9 @@
             "7",
             "10"
         ],
-        "en": "Seventy",
-        "fi": "Seitsemänkymmentä",
-        "nl": "Zeventig"
+        "en": "seventy",
+        "fi": "seitsemänkymmentä",
+        "nl": "zeventig"
     },
     "80": {
         "level": {
@@ -410,9 +410,9 @@
             "8",
             "10"
         ],
-        "en": "Eighty",
-        "fi": "Kahdeksankymmentä",
-        "nl": "Tachtig"
+        "en": "eighty",
+        "fi": "kahdeksankymmentä",
+        "nl": "tachtig"
     },
     "90": {
         "level": {
@@ -423,9 +423,9 @@
             "9",
             "10"
         ],
-        "en": "Ninety",
-        "fi": "Yhdeksänkymmentä",
-        "nl": "Negentig"
+        "en": "ninety",
+        "fi": "yhdeksänkymmentä",
+        "nl": "negentig"
     },
     "100": {
         "level": {
@@ -435,9 +435,9 @@
             ],
             "A2": "EP"
         },
-        "en": "Hundred",
-        "fi": "Sata",
-        "nl": "Honderd"
+        "en": "hundred",
+        "fi": "sata",
+        "nl": "honderd"
     },
     "200": {
         "level": {
@@ -450,9 +450,9 @@
             "2",
             "100"
         ],
-        "en": "Two hundred",
-        "fi": "Kaksisataa",
-        "nl": "Tweehonderd"
+        "en": "two hundred",
+        "fi": "kaksisataa",
+        "nl": "tweehonderd"
     },
     "1000": {
         "level": {
@@ -462,9 +462,9 @@
             ],
             "A2": "EP"
         },
-        "en": "Thousand",
-        "fi": "Tuhat",
-        "nl": "Duizend"
+        "en": "thousand",
+        "fi": "tuhat",
+        "nl": "duizend"
     },
     "2000": {
         "level": {
@@ -477,8 +477,8 @@
             "2",
             "1000"
         ],
-        "en": "Two thousand",
-        "fi": "Kaksituhatta",
-        "nl": "Tweeduizend"
+        "en": "two thousand",
+        "fi": "kaksituhatta",
+        "nl": "tweeduizend"
     }
 }
\ No newline at end of file
diff --git a/src/topics/countries.json b/src/topics/countries.json
index d663af8e..fc45de08 100644
--- a/src/topics/countries.json
+++ b/src/topics/countries.json
@@ -8,14 +8,14 @@
             ]
         },
         "singular": {
-            "en": "Country",
-            "fi": "Maa;geography",
-            "nl": "Het land"
+            "en": "country",
+            "fi": "maa;geography",
+            "nl": "het land"
         },
         "plural": {
-            "en": "Countries",
-            "fi": "Maat;geography",
-            "nl": "De landen"
+            "en": "countries",
+            "fi": "maat;geography",
+            "nl": "de landen"
         }
     },
     "finland": {
@@ -23,7 +23,7 @@
             "nl": "country"
         },
         "en": "Finland",
-        "fi": "Suomi;country",
+        "fi": "Suomi",
         "nl": "Finland"
     },
     "estland": {
@@ -31,22 +31,22 @@
             "nl": "country"
         },
         "en": "Estland",
-        "fi": "Viro;country",
+        "fi": "Viro",
         "nl": "Estland"
     },
     "denmark": {
         "en": "Denmark",
-        "fi": "Tanska;country",
+        "fi": "Tanska",
         "nl": "Denemarken"
     },
     "norway": {
         "en": "Norway",
-        "fi": "Norja;country",
+        "fi": "Norja",
         "nl": "Noorwegen"
     },
     "sweden": {
         "en": "Sweden",
-        "fi": "Ruotsi;country",
+        "fi": "Ruotsi",
         "nl": "Zweden"
     },
     "russia": {
@@ -54,7 +54,7 @@
             "nl": "country"
         },
         "en": "Russia",
-        "fi": "Venäjä;country",
+        "fi": "Venäjä",
         "nl": "Rusland"
     },
     "belgium": {
@@ -76,12 +76,12 @@
             "nl": "country"
         },
         "en": "Germany",
-        "fi": "Saksa;country",
+        "fi": "Saksa",
         "nl": "Duitsland"
     },
     "france": {
         "en": "France",
-        "fi": "Ranska;country",
+        "fi": "Ranska",
         "nl": "Frankrijk"
     },
     "england": {
@@ -89,7 +89,7 @@
             "nl": "country"
         },
         "en": "England",
-        "fi": "Englanti;country",
+        "fi": "Englanti",
         "nl": "Engeland"
     },
     "iceland": {
@@ -97,32 +97,32 @@
             "nl": "country"
         },
         "en": "Iceland",
-        "fi": "Islanti;country",
+        "fi": "Islanti",
         "nl": "IJsland"
     },
     "china": {
         "en": "China",
-        "fi": "Kiina;country",
+        "fi": "Kiina",
         "nl": "China"
     },
     "hungary": {
         "en": "Hungary",
-        "fi": "Unkari;country",
+        "fi": "Unkari",
         "nl": "Hongarije"
     },
     "japan": {
         "en": "Japan",
-        "fi": "Japani;country",
+        "fi": "Japani",
         "nl": "Japan"
     },
     "korea": {
         "en": "Korea",
-        "fi": "Korea;country",
+        "fi": "Korea",
         "nl": "Korea"
     },
     "spain": {
         "en": "Spain",
-        "fi": "Espanja;country",
+        "fi": "Espanja",
         "nl": "Spanje"
     }
 }
\ No newline at end of file
diff --git a/src/topics/days.json b/src/topics/days.json
index a7042848..cbba674d 100644
--- a/src/topics/days.json
+++ b/src/topics/days.json
@@ -8,14 +8,14 @@
             ]
         },
         "singular": {
-            "en": "Day",
-            "fi": "Päivä",
-            "nl": "De dag"
+            "en": "day",
+            "fi": "päivä",
+            "nl": "de dag"
         },
         "plural": {
-            "en": "Days",
-            "fi": "Päivät",
-            "nl": "De dagen"
+            "en": "days",
+            "fi": "päivät",
+            "nl": "de dagen"
         }
     },
     "week": {
@@ -27,14 +27,14 @@
             ]
         },
         "singular": {
-            "en": "Week",
-            "fi": "Viikko",
-            "nl": "De week"
+            "en": "week",
+            "fi": "viikko",
+            "nl": "de week"
         },
         "plural": {
-            "en": "Weeks",
-            "fi": "Viikot",
-            "nl": "De weken"
+            "en": "weeks",
+            "fi": "viikot",
+            "nl": "de weken"
         }
     },
     "weekend": {
@@ -46,14 +46,14 @@
         },
         "roots": "week",
         "singular": {
-            "en": "Weekend",
-            "fi": "Viikonloppu",
-            "nl": "Het weekend"
+            "en": "weekend",
+            "fi": "viikonloppu",
+            "nl": "het weekend"
         },
         "plural": {
-            "en": "Weekends",
-            "fi": "Viikonloput",
-            "nl": "De weekenden"
+            "en": "weekends",
+            "fi": "viikonloput",
+            "nl": "de weekenden"
         }
     },
     "days of the week": {
@@ -61,9 +61,9 @@
             "day",
             "week"
         ],
-        "en": "Days of the week",
-        "fi": "Viikonpäivät",
-        "nl": "De dagen van de week"
+        "en": "days of the week",
+        "fi": "viikonpäivät",
+        "nl": "de dagen van de week"
     },
     "monday": {
         "level": {
@@ -81,20 +81,20 @@
         },
         "singular": {
             "en": "Monday",
-            "fi": "Maanantai",
-            "nl": "Maandag|De maandag"
+            "fi": "maanantai",
+            "nl": "maandag|de maandag"
         },
         "plural": {
             "en": "Mondays",
-            "fi": "Maanantait",
-            "nl": "De maandagen"
+            "fi": "maanantait",
+            "nl": "de maandagen"
         }
     },
     "on monday": {
         "roots": "monday",
-        "en": "On Monday",
-        "fi": "Maanantaina",
-        "nl": "Op maandag"
+        "en": "on Monday",
+        "fi": "maanantaina",
+        "nl": "op maandag"
     },
     "tuesday": {
         "level": {
@@ -109,13 +109,13 @@
         },
         "singular": {
             "en": "Tuesday",
-            "fi": "Tiistai",
-            "nl": "Dinsdag|De dinsdag"
+            "fi": "tiistai",
+            "nl": "dinsdag|de dinsdag"
         },
         "plural": {
             "en": "Tuesdays",
-            "fi": "Tiistait",
-            "nl": "De dinsdagen"
+            "fi": "tiistait",
+            "nl": "de dinsdagen"
         }
     },
     "wednesday": {
@@ -132,20 +132,20 @@
         },
         "singular": {
             "en": "Wednesday",
-            "fi": "Keskiviikko",
-            "nl": "Woensdag|De woensdag"
+            "fi": "keskiviikko",
+            "nl": "woensdag|de woensdag"
         },
         "plural": {
             "en": "Wednesdays",
-            "fi": "Keskiviikot",
-            "nl": "De woensdagen"
+            "fi": "keskiviikot",
+            "nl": "de woensdagen"
         }
     },
     "on wednesday": {
         "roots": "wednesday",
-        "en": "On Wednesday",
-        "fi": "Keskiviikkona",
-        "nl": "Op woensdag"
+        "en": "on Wednesday",
+        "fi": "keskiviikkona",
+        "nl": "op woensdag"
     },
     "thursday": {
         "level": {
@@ -160,13 +160,13 @@
         },
         "singular": {
             "en": "Thursday",
-            "fi": "Torstai",
-            "nl": "Donderdag|De donderdag"
+            "fi": "torstai",
+            "nl": "donderdag|de donderdag"
         },
         "plural": {
             "en": "Thursdays",
-            "fi": "Torstait",
-            "nl": "De donderdagen"
+            "fi": "torstait",
+            "nl": "de donderdagen"
         }
     },
     "friday": {
@@ -182,13 +182,13 @@
         },
         "singular": {
             "en": "Friday",
-            "fi": "Perjantai",
-            "nl": "Vrijdag|De vrijdag"
+            "fi": "perjantai",
+            "nl": "vrijdag|de vrijdag"
         },
         "plural": {
             "en": "Fridays",
-            "fi": "Perjantait",
-            "nl": "De vrijdagen"
+            "fi": "perjantait",
+            "nl": "de vrijdagen"
         }
     },
     "saturday": {
@@ -204,13 +204,13 @@
         },
         "singular": {
             "en": "Saturday",
-            "fi": "Lauantai",
-            "nl": "Zaterdag|De zaterdag"
+            "fi": "lauantai",
+            "nl": "zaterdag|de zaterdag"
         },
         "plural": {
             "en": "Saturdays",
-            "fi": "Lauantait",
-            "nl": "De zaterdagen"
+            "fi": "lauantait",
+            "nl": "de zaterdagen"
         }
     },
     "sunday": {
@@ -226,13 +226,13 @@
         },
         "singular": {
             "en": "Sunday",
-            "fi": "Sunnuntai",
-            "nl": "Zondag|De zondag"
+            "fi": "sunnuntai",
+            "nl": "zondag|de zondag"
         },
         "plural": {
             "en": "Sundays",
-            "fi": "Sunnuntait",
-            "nl": "De zondagen"
+            "fi": "sunnuntait",
+            "nl": "de zondagen"
         }
     },
     "today": {
@@ -246,9 +246,9 @@
         "roots": {
             "en": "day"
         },
-        "en": "Today",
-        "fi": "Tänään",
-        "nl": "Vandaag"
+        "en": "today",
+        "fi": "tänään",
+        "nl": "vandaag"
     },
     "yesterday": {
         "level": {
@@ -261,9 +261,9 @@
         "roots": {
             "en": "day"
         },
-        "en": "Yesterday",
-        "fi": "Eilen",
-        "nl": "Gisteren"
+        "en": "yesterday",
+        "fi": "eilen",
+        "nl": "gisteren"
     },
     "tomorrow": {
         "level": {
@@ -273,9 +273,9 @@
                 "OD"
             ]
         },
-        "en": "Tomorrow",
-        "fi": "Huomenna",
-        "nl": "Morgen"
+        "en": "tomorrow",
+        "fi": "huomenna",
+        "nl": "morgen"
     },
     "this week": {
         "level": {
@@ -283,9 +283,9 @@
             "OD": "A1"
         },
         "roots": "week",
-        "en": "This week",
-        "fi": "Tällä viikolla",
-        "nl": "Deze week"
+        "en": "this week",
+        "fi": "tällä viikolla",
+        "nl": "deze week"
     },
     "last week": {
         "level": {
@@ -295,9 +295,9 @@
             ]
         },
         "roots": "week",
-        "en": "Last week",
-        "fi": "Viime viikolla",
-        "nl": "Vorige week"
+        "en": "last week",
+        "fi": "viime viikolla",
+        "nl": "vorige week"
     },
     "next week": {
         "level": {
@@ -307,9 +307,9 @@
             ]
         },
         "roots": "week",
-        "en": "Next week",
-        "fi": "Ensi viikolla",
-        "nl": "Volgende week"
+        "en": "next week",
+        "fi": "ensi viikolla",
+        "nl": "volgende week"
     },
     "today it is monday": {
         "roots": [
diff --git a/src/topics/degrees_of_comparison.json b/src/topics/degrees_of_comparison.json
index 9f1238de..cab962b8 100644
--- a/src/topics/degrees_of_comparison.json
+++ b/src/topics/degrees_of_comparison.json
@@ -9,19 +9,19 @@
         },
         "antonym": "big",
         "positive degree": {
-            "en": "Small",
-            "fi": "Pieni",
-            "nl": "Klein"
+            "en": "small",
+            "fi": "pieni",
+            "nl": "klein"
         },
         "comparative degree": {
-            "en": "Smaller",
-            "fi": "Pienempi",
-            "nl": "Kleiner"
+            "en": "smaller",
+            "fi": "pienempi",
+            "nl": "kleiner"
         },
         "superlative degree": {
-            "en": "Smallest",
-            "fi": "Pienin",
-            "nl": "Kleinst"
+            "en": "smallest",
+            "fi": "pienin",
+            "nl": "kleinst"
         }
     },
     "important": {
@@ -32,19 +32,19 @@
             ]
         },
         "positive degree": {
-            "en": "Important",
-            "fi": "Tärkeä",
-            "nl": "Belangrijk"
+            "en": "important",
+            "fi": "tärkeä",
+            "nl": "belangrijk"
         },
         "comparative degree": {
-            "en": "More important",
-            "fi": "Tärkeämpi",
-            "nl": "Belangrijker"
+            "en": "more important",
+            "fi": "tärkeämpi",
+            "nl": "belangrijker"
         },
         "superlative degree": {
-            "en": "Most important",
-            "fi": "Tärkein",
-            "nl": "Belangrijkst"
+            "en": "most important",
+            "fi": "tärkein",
+            "nl": "belangrijkst"
         }
     },
     "expensive": {
@@ -56,19 +56,19 @@
         },
         "antonym": "cheap",
         "positive degree": {
-            "en": "Expensive",
-            "fi": "Kallis",
-            "nl": "Duur"
+            "en": "expensive",
+            "fi": "kallis",
+            "nl": "duur"
         },
         "comparative degree": {
-            "en": "More expensive",
-            "fi": "Kalliimpi",
-            "nl": "Duurder"
+            "en": "more expensive",
+            "fi": "kalliimpi",
+            "nl": "duurder"
         },
         "superlative degree": {
-            "en": "Most expensive",
-            "fi": "Kallein",
-            "nl": "Duurst"
+            "en": "most expensive",
+            "fi": "kallein",
+            "nl": "duurst"
         }
     },
     "cheap": {
@@ -80,19 +80,19 @@
         },
         "antonym": "expensive",
         "positive degree": {
-            "en": "Cheap",
-            "fi": "Halpa",
-            "nl": "Goedkoop"
+            "en": "cheap",
+            "fi": "halpa",
+            "nl": "goedkoop"
         },
         "comparative degree": {
-            "en": "Cheaper",
-            "fi": "Halvempi",
-            "nl": "Goedkoper"
+            "en": "cheaper",
+            "fi": "halvempi",
+            "nl": "goedkoper"
         },
         "superlative degree": {
-            "en": "Cheapest",
-            "fi": "Halvin",
-            "nl": "Goedkoopst"
+            "en": "cheapest",
+            "fi": "halvin",
+            "nl": "goedkoopst"
         }
     },
     "hot": {
@@ -103,19 +103,19 @@
             ]
         },
         "positive degree": {
-            "en": "Hot",
-            "fi": "Kuuma",
-            "nl": "Heet"
+            "en": "hot",
+            "fi": "kuuma",
+            "nl": "heet"
         },
         "comparative degree": {
-            "en": "Hotter",
-            "fi": "Kuumempi",
-            "nl": "Heter"
+            "en": "hotter",
+            "fi": "kuumempi",
+            "nl": "heter"
         },
         "superlative degree": {
-            "en": "Hottest",
-            "fi": "Kuumin",
-            "nl": "Heetst"
+            "en": "hottest",
+            "fi": "kuumin",
+            "nl": "heetst"
         }
     },
     "cold": {
@@ -128,19 +128,19 @@
         },
         "antonym": "warm",
         "positive degree": {
-            "en": "Cold",
-            "fi": "Kylmä",
-            "nl": "Koud"
+            "en": "cold",
+            "fi": "kylmä",
+            "nl": "koud"
         },
         "comparative degree": {
-            "en": "Colder",
-            "fi": "Kylmempi",
-            "nl": "Kouder"
+            "en": "colder",
+            "fi": "kylmempi",
+            "nl": "kouder"
         },
         "superlative degree": {
-            "en": "Coldest",
-            "fi": "Kylmin",
-            "nl": "Koudst"
+            "en": "coldest",
+            "fi": "kylmin",
+            "nl": "koudst"
         }
     },
     "light (not heavy)": {
@@ -149,19 +149,19 @@
             "A2": "EP"
         },
         "positive degree": {
-            "en": "Light",
-            "fi": "Kevyt",
-            "nl": "Licht"
+            "en": "light",
+            "fi": "kevyt",
+            "nl": "licht"
         },
         "comparative degree": {
-            "en": "Lighter",
-            "fi": "Kevyempi",
-            "nl": "Lichter"
+            "en": "lighter",
+            "fi": "kevyempi",
+            "nl": "lichter"
         },
         "superlative degree": {
-            "en": "Lightest",
-            "fi": "Kevyin",
-            "nl": "Lichtst"
+            "en": "lightest",
+            "fi": "kevyin",
+            "nl": "lichtst"
         }
     },
     "easy": {
@@ -174,19 +174,19 @@
         },
         "antonym": "hard",
         "positive degree": {
-            "en": "Easy",
-            "fi": "Helppo",
-            "nl": "Makkelijk"
+            "en": "easy",
+            "fi": "helppo",
+            "nl": "makkelijk"
         },
         "comparative degree": {
-            "en": "Easier",
-            "fi": "Helpompi",
-            "nl": "Makkelijker"
+            "en": "easier",
+            "fi": "helpompi",
+            "nl": "makkelijker"
         },
         "superlative degree": {
-            "en": "Easiest",
-            "fi": "Helpoin",
-            "nl": "Makkelijkst"
+            "en": "easiest",
+            "fi": "helpoin",
+            "nl": "makkelijkst"
         }
     },
     "hard": {
@@ -199,19 +199,19 @@
         },
         "antonym": "easy",
         "positive degree": {
-            "en": "Hard",
-            "fi": "Vaikea",
+            "en": "hard",
+            "fi": "vaikea",
             "nl": "Moeilijk"
         },
         "comparative degree": {
-            "en": "Harder",
-            "fi": "Vaikeampi",
-            "nl": "Moeilijker"
+            "en": "harder",
+            "fi": "vaikeampi",
+            "nl": "moeilijker"
         },
         "superlative degree": {
-            "en": "Hardest",
-            "fi": "Vaikein",
-            "nl": "Moeilijkst"
+            "en": "hardest",
+            "fi": "vaikein",
+            "nl": "moeilijkst"
         }
     },
     "beautiful": {
@@ -223,19 +223,19 @@
             ]
         },
         "positive degree": {
-            "en": "Beautiful",
-            "fi": "Kaunis",
-            "nl": "Mooi"
+            "en": "beautiful",
+            "fi": "kaunis",
+            "nl": "mooi"
         },
         "comparative degree": {
-            "en": "More beautiful",
-            "fi": "Kauniimpi",
-            "nl": "Mooier"
+            "en": "more beautiful",
+            "fi": "kauniimpi",
+            "nl": "mooier"
         },
         "superlative degree": {
-            "en": "Most beautiful",
-            "fi": "Kaunein",
-            "nl": "Mooist"
+            "en": "most beautiful",
+            "fi": "kaunein",
+            "nl": "mooist"
         }
     },
     "new": {
@@ -248,19 +248,19 @@
         },
         "antonym": "old",
         "positive degree": {
-            "en": "New",
-            "fi": "Uusi",
-            "nl": "Nieuw"
+            "en": "new",
+            "fi": "uusi",
+            "nl": "nieuw"
         },
         "comparative degree": {
-            "en": "Newer",
-            "fi": "Uudempi",
-            "nl": "Nieuwer"
+            "en": "newer",
+            "fi": "uudempi",
+            "nl": "nieuwer"
         },
         "superlative degree": {
-            "en": "Newest",
-            "fi": "Uusin",
-            "nl": "Nieuwst"
+            "en": "newest",
+            "fi": "uusin",
+            "nl": "nieuwst"
         }
     },
     "old": {
@@ -273,19 +273,19 @@
         },
         "antonym": "new",
         "positive degree": {
-            "en": "Old",
-            "fi": "Vanha",
-            "nl": "Oud"
+            "en": "old",
+            "fi": "vanha",
+            "nl": "oud"
         },
         "comparative degree": {
-            "en": "Older",
-            "fi": "Vanhempi",
-            "nl": "Ouder"
+            "en": "older",
+            "fi": "vanhempi",
+            "nl": "ouder"
         },
         "superlative degree": {
-            "en": "Oldest",
-            "fi": "Vanhin",
-            "nl": "Oudst"
+            "en": "oldest",
+            "fi": "vanhin",
+            "nl": "oudst"
         }
     },
     "cute": {
@@ -294,19 +294,19 @@
             "none": "EP"
         },
         "positive degree": {
-            "en": "Cute",
-            "fi": "Söpö",
-            "nl": "Schattig"
+            "en": "cute",
+            "fi": "söpö",
+            "nl": "schattig"
         },
         "comparative degree": {
-            "en": "Cuter",
-            "fi": "Söpömpi",
-            "nl": "Schattiger"
+            "en": "cuter",
+            "fi": "söpömpi",
+            "nl": "schattiger"
         },
         "superlative degree": {
-            "en": "Cutest",
-            "fi": "Söpöin",
-            "nl": "Schattigst"
+            "en": "cutest",
+            "fi": "söpöin",
+            "nl": "schattigst"
         }
     },
     "fast": {
@@ -319,19 +319,19 @@
         },
         "antonym": "slow",
         "positive degree": {
-            "en": "Fast",
-            "fi": "Nopea",
-            "nl": "Snel"
+            "en": "fast",
+            "fi": "nopea",
+            "nl": "snel"
         },
         "comparative degree": {
-            "en": "Faster",
-            "fi": "Nopeampi",
-            "nl": "Sneller"
+            "en": "faster",
+            "fi": "nopeampi",
+            "nl": "sneller"
         },
         "superlative degree": {
-            "en": "Fastest",
-            "fi": "Nopein",
-            "nl": "Snelst"
+            "en": "fastest",
+            "fi": "nopein",
+            "nl": "snelst"
         }
     },
     "quiet": {
@@ -340,19 +340,19 @@
             "A2": "EP"
         },
         "positive degree": {
-            "en": "Quiet",
-            "fi": "Hiljainen",
-            "nl": "Stil"
+            "en": "quiet",
+            "fi": "hiljainen",
+            "nl": "stil"
         },
         "comparative degree": {
-            "en": "Quieter",
-            "fi": "Hiljaisempi",
-            "nl": "Stiller"
+            "en": "quieter",
+            "fi": "hiljaisempi",
+            "nl": "stiller"
         },
         "superlative degree": {
-            "en": "Quietest",
-            "fi": "Hiljaisin",
-            "nl": "Stilst"
+            "en": "quietest",
+            "fi": "hiljaisin",
+            "nl": "stilst"
         }
     },
     "fresh": {
@@ -363,19 +363,19 @@
             ]
         },
         "positive degree": {
-            "en": "Fresh",
-            "fi": "Tuore",
-            "nl": "Vers"
+            "en": "fresh",
+            "fi": "tuore",
+            "nl": "vers"
         },
         "comparative degree": {
-            "en": "Fresher",
-            "fi": "Tuoreempi",
-            "nl": "Verser"
+            "en": "fresher",
+            "fi": "tuoreempi",
+            "nl": "verser"
         },
         "superlative degree": {
-            "en": "Freshest",
-            "fi": "Tuorein",
-            "nl": "Verst"
+            "en": "freshest",
+            "fi": "tuorein",
+            "nl": "verst"
         }
     },
     "warm": {
@@ -387,19 +387,19 @@
         },
         "antonym": "cold",
         "positive degree": {
-            "en": "Warm",
-            "fi": "Lämmin",
-            "nl": "Warm"
+            "en": "warm",
+            "fi": "lämmin",
+            "nl": "warm"
         },
         "comparative degree": {
-            "en": "Warmer",
-            "fi": "Lämpimämpi",
-            "nl": "Warmer"
+            "en": "warmer",
+            "fi": "lämpimämpi",
+            "nl": "warmer"
         },
         "superlative degree": {
-            "en": "Warmest",
-            "fi": "Lämpimin",
-            "nl": "Warmst"
+            "en": "warmest",
+            "fi": "lämpimin",
+            "nl": "warmst"
         }
     },
     "round": {
@@ -410,19 +410,19 @@
             ]
         },
         "positive degree": {
-            "en": "Round",
-            "fi": "Pyöreä",
-            "nl": "Rond"
+            "en": "round",
+            "fi": "pyöreä",
+            "nl": "rond"
         },
         "comparative degree": {
-            "en": "Rounder",
-            "fi": "Pyöreämpi",
-            "nl": "Ronder"
+            "en": "rounder",
+            "fi": "pyöreämpi",
+            "nl": "ronder"
         },
         "superlative degree": {
-            "en": "Roundest",
-            "fi": "Pyörein",
-            "nl": "Rondst"
+            "en": "roundest",
+            "fi": "pyörein",
+            "nl": "rondst"
         }
     },
     "strange": {
@@ -434,19 +434,19 @@
             ]
         },
         "positive degree": {
-            "en": "Strange",
-            "fi": "Outo",
-            "nl": "Vreemd"
+            "en": "strange",
+            "fi": "outo",
+            "nl": "vreemd"
         },
         "comparative degree": {
-            "en": "Stranger",
-            "fi": "Oudompi",
-            "nl": "Vreemder"
+            "en": "stranger",
+            "fi": "oudompi",
+            "nl": "vreemder"
         },
         "superlative degree": {
-            "en": "Strangest",
-            "fi": "Oudoin",
-            "nl": "Vreemdst"
+            "en": "strangest",
+            "fi": "oudoin",
+            "nl": "vreemdst"
         }
     },
     "honest": {
@@ -457,19 +457,19 @@
             ]
         },
         "positive degree": {
-            "en": "Honest",
-            "fi": "Rehellinen",
-            "nl": "Eerlijk"
+            "en": "honest",
+            "fi": "rehellinen",
+            "nl": "eerlijk"
         },
         "comparative degree": {
-            "en": "More honest",
-            "fi": "Rehellisempi",
-            "nl": "Eerlijker"
+            "en": "more honest",
+            "fi": "rehellisempi",
+            "nl": "eerlijker"
         },
         "superlative degree": {
-            "en": "Most honest",
-            "fi": "Rehellisin",
-            "nl": "Eerlijkst"
+            "en": "most honest",
+            "fi": "rehellisin",
+            "nl": "eerlijkst"
         }
     },
     "long": {
@@ -482,19 +482,19 @@
         },
         "antonym": "short",
         "positive degree": {
-            "en": "Long",
-            "fi": "Pitkä",
-            "nl": "Lang"
+            "en": "long",
+            "fi": "pitkä",
+            "nl": "lang"
         },
         "comparative degree": {
-            "en": "Longer",
-            "fi": "Pidempi",
-            "nl": "Langer"
+            "en": "longer",
+            "fi": "pidempi",
+            "nl": "langer"
         },
         "superlative degree": {
-            "en": "Longest",
-            "fi": "Pisin",
-            "nl": "Langst"
+            "en": "longest",
+            "fi": "pisin",
+            "nl": "langst"
         }
     },
     "short": {
@@ -507,19 +507,19 @@
         },
         "antonym": "long",
         "positive degree": {
-            "en": "Short",
-            "fi": "Lyhyt",
-            "nl": "Kort"
+            "en": "short",
+            "fi": "lyhyt",
+            "nl": "kort"
         },
         "comparative degree": {
-            "en": "Shorter",
-            "fi": "Lyhyempi",
-            "nl": "Korter"
+            "en": "shorter",
+            "fi": "lyhyempi",
+            "nl": "korter"
         },
         "superlative degree": {
-            "en": "Shortest",
-            "fi": "Lyhyin",
-            "nl": "Kortst"
+            "en": "shortest",
+            "fi": "lyhyin",
+            "nl": "kortst"
         }
     },
     "tasty": {
@@ -530,19 +530,19 @@
             ]
         },
         "positive degree": {
-            "en": "Tasty",
-            "fi": "Maukas",
-            "nl": "Lekker"
+            "en": "tasty",
+            "fi": "maukas",
+            "nl": "lekker"
         },
         "comparative degree": {
-            "en": "Tastier",
-            "fi": "Maukkaampi",
-            "nl": "Lekkerder"
+            "en": "tastier",
+            "fi": "maukkaampi",
+            "nl": "lekkerder"
         },
         "superlative degree": {
-            "en": "Tastiest",
-            "fi": "Maukkain",
-            "nl": "Lekkerst"
+            "en": "tastiest",
+            "fi": "maukkain",
+            "nl": "lekkerst"
         }
     },
     "slow": {
@@ -554,19 +554,19 @@
         },
         "antonym": "fast",
         "positive degree": {
-            "en": "Slow",
-            "fi": "Hidas",
-            "nl": "Langzaam"
+            "en": "slow",
+            "fi": "hidas",
+            "nl": "langzaam"
         },
         "comparative degree": {
-            "en": "Slower",
-            "fi": "Hitaampi",
-            "nl": "Langzamer"
+            "en": "slower",
+            "fi": "hitaampi",
+            "nl": "langzamer"
         },
         "superlative degree": {
-            "en": "Slowest",
-            "fi": "Hitain",
-            "nl": "Langzaamst"
+            "en": "slowest",
+            "fi": "hitain",
+            "nl": "langzaamst"
         }
     },
     "sweet": {
@@ -575,19 +575,19 @@
             "A2": "OD"
         },
         "positive degree": {
-            "en": "Sweet",
-            "fi": "Makea",
-            "nl": "Zoet"
+            "en": "sweet",
+            "fi": "makea",
+            "nl": "zoet"
         },
         "comparative degree": {
-            "en": "Sweter",
-            "fi": "Makeampi",
-            "nl": "Zoeter"
+            "en": "sweeter",
+            "fi": "makeampi",
+            "nl": "zoeter"
         },
         "superlative degree": {
-            "en": "Sweetest",
-            "fi": "Makein",
-            "nl": "Zoetst"
+            "en": "sweetest",
+            "fi": "makein",
+            "nl": "zoetst"
         }
     },
     "big": {
@@ -600,28 +600,28 @@
         },
         "antonym": "small",
         "positive degree": {
-            "en": "Big",
+            "en": "big",
             "fi": [
-                "Iso",
-                "Suuri"
+                "iso",
+                "suuri"
             ],
-            "nl": "Groot"
+            "nl": "groot"
         },
         "comparative degree": {
-            "en": "Bigger",
+            "en": "bigger",
             "fi": [
-                "Isompi",
-                "Suurempi"
+                "isompi",
+                "suurempi"
             ],
-            "nl": "Groter"
+            "nl": "groter"
         },
         "superlative degree": {
-            "en": "Biggest",
+            "en": "biggest",
             "fi": [
-                "Isoin",
-                "Suurin"
+                "isoin",
+                "suurin"
             ],
-            "nl": "Grootst"
+            "nl": "grootst"
         }
     },
     "nice": {
@@ -633,28 +633,28 @@
             ]
         },
         "positive degree": {
-            "en": "Nice",
+            "en": "nice",
             "fi": [
-                "Kiva",
-                "Mukava"
+                "kiva",
+                "mukava"
             ],
             "nl": "Leuk"
         },
         "comparative degree": {
-            "en": "Nicer",
+            "en": "nicer",
             "fi": [
-                "Kivampi|Kivempt",
-                "Mukavampi"
+                "kivampi|kivempt",
+                "mukavampi"
             ],
             "nl": "Leuker"
         },
         "superlative degree": {
-            "en": "Nicest",
+            "en": "nicest",
             "fi": [
-                "Kivoin",
-                "Mukavin"
+                "kivoin",
+                "mukavin"
             ],
-            "nl": "Leukst"
+            "nl": "leukst"
         }
     },
     "wet": {
@@ -666,19 +666,19 @@
         },
         "antonym": "dry",
         "positive degree": {
-            "en": "Wet",
-            "fi": "Märkä",
-            "nl": "Nat"
+            "en": "wet",
+            "fi": "märkä",
+            "nl": "nat"
         },
         "comparative degree": {
-            "en": "Wetter",
-            "fi": "Märempi",
-            "nl": "Natter"
+            "en": "wetter",
+            "fi": "märempi",
+            "nl": "natter"
         },
         "superlative degree": {
-            "en": "Wettest",
-            "fi": "Märin",
-            "nl": "Natst"
+            "en": "wettest",
+            "fi": "märin",
+            "nl": "natst"
         }
     },
     "dry": {
@@ -690,19 +690,19 @@
         },
         "antonym": "wet",
         "positive degree": {
-            "en": "Dry",
-            "fi": "Kuiva",
-            "nl": "Droog"
+            "en": "dry",
+            "fi": "kuiva",
+            "nl": "droog"
         },
         "comparative degree": {
-            "en": "Dryer",
-            "fi": "Kuivempi",
-            "nl": "Droger"
+            "en": "dryer",
+            "fi": "kuivempi",
+            "nl": "droger"
         },
         "superlative degree": {
-            "en": "Dryest",
-            "fi": "Kuivin",
-            "nl": "Droogst"
+            "en": "dryest",
+            "fi": "kuivin",
+            "nl": "droogst"
         }
     },
     "good": {
@@ -714,19 +714,19 @@
         },
         "antonym": "bad",
         "positive degree": {
-            "en": "Good",
-            "fi": "Hyvä",
-            "nl": "Goed"
+            "en": "good",
+            "fi": "hyvä",
+            "nl": "goed"
         },
         "comparative degree": {
-            "en": "Better",
-            "fi": "Parempi",
-            "nl": "Beter"
+            "en": "better",
+            "fi": "parempi",
+            "nl": "beter"
         },
         "superlative degree": {
-            "en": "Best",
-            "fi": "Paras",
-            "nl": "Best"
+            "en": "best",
+            "fi": "paras",
+            "nl": "best"
         }
     },
     "bad": {
@@ -738,19 +738,19 @@
         },
         "antonym": "good",
         "positive degree": {
-            "en": "Bad",
-            "fi": "Huono",
-            "nl": "Slecht"
+            "en": "bad",
+            "fi": "huono",
+            "nl": "slecht"
         },
         "comparative degree": {
-            "en": "Badder",
-            "fi": "Huonompi",
-            "nl": "Slechter"
+            "en": "badder",
+            "fi": "huonompi",
+            "nl": "slechter"
         },
         "superlative degree": {
-            "en": "Baddest",
-            "fi": "Huonoin",
-            "nl": "Slechtst"
+            "en": "baddest",
+            "fi": "huonoin",
+            "nl": "slechtst"
         }
     },
     "happy": {
@@ -761,19 +761,19 @@
             ]
         },
         "positive degree": {
-            "en": "Happy",
-            "fi": "Onnellinen",
-            "nl": "Gelukkig"
+            "en": "happy",
+            "fi": "onnellinen",
+            "nl": "gelukkig"
         },
         "comparative degree": {
-            "en": "Happier",
-            "fi": "Onnellisempi",
-            "nl": "Gelukkiger"
+            "en": "happier",
+            "fi": "onnellisempi",
+            "nl": "gelukkiger"
         },
         "superlative degree": {
-            "en": "Happiest",
-            "fi": "Onnellisin",
-            "nl": "Gelukkigst"
+            "en": "happiest",
+            "fi": "onnellisin",
+            "nl": "gelukkigst"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/family.json b/src/topics/family.json
index ca14981d..376db107 100644
--- a/src/topics/family.json
+++ b/src/topics/family.json
@@ -7,9 +7,9 @@
                 "OD"
             ]
         },
-        "en": "Family",
-        "fi": "Perhe",
-        "nl": "De familie"
+        "en": "family",
+        "fi": "perhe",
+        "nl": "de familie"
     },
     "grandma": {
         "level": {
@@ -17,20 +17,20 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Grandma",
+            "en": "grandma",
             "fi": [
-                "Mummo",
-                "Mummi"
+                "mummo",
+                "mummi"
             ],
-            "nl": "De oma"
+            "nl": "de oma"
         },
         "plural": {
-            "en": "Grandmas",
+            "en": "grandmas",
             "fi": [
-                "Mummot",
-                "Mummit"
+                "mummot",
+                "mummit"
             ],
-            "nl": "De oma's"
+            "nl": "de oma's"
         }
     },
     "grandpa": {
@@ -39,20 +39,20 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Grandpa",
+            "en": "grandpa",
             "fi": [
-                "Vaari",
-                "Ukki"
+                "vaari",
+                "ukki"
             ],
-            "nl": "De opa"
+            "nl": "de opa"
         },
         "plural": {
-            "en": "Grandpas",
+            "en": "grandpas",
             "fi": [
-                "Vaarit",
-                "Ukit"
+                "vaarit",
+                "ukit"
             ],
-            "nl": "De opa's"
+            "nl": "de opa's"
         }
     },
     "grandmother": {
@@ -72,14 +72,14 @@
             ]
         },
         "singular": {
-            "en": "Grandmother",
-            "fi": "Isoäiti",
-            "nl": "De grootmoeder"
+            "en": "grandmother",
+            "fi": "isoäiti",
+            "nl": "de grootmoeder"
         },
         "plural": {
-            "en": "Grandmothers",
-            "fi": "Isoäidit",
-            "nl": "De grootmoeders"
+            "en": "grandmothers",
+            "fi": "isoäidit",
+            "nl": "de grootmoeders"
         }
     },
     "grandfather": {
@@ -99,14 +99,14 @@
             ]
         },
         "singular": {
-            "en": "Grandfather",
-            "fi": "Isoisä",
-            "nl": "De grootvader"
+            "en": "grandfather",
+            "fi": "isoisä",
+            "nl": "de grootvader"
         },
         "plural": {
-            "en": "Grandfathers",
-            "fi": "Isoisät",
-            "nl": "De grootvaders"
+            "en": "grandfathers",
+            "fi": "isoisät",
+            "nl": "de grootvaders"
         }
     },
     "married": {
@@ -114,18 +114,18 @@
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "Married",
-        "fi": "Naimisissa",
-        "nl": "Getrouwd"
+        "en": "married",
+        "fi": "naimisissa",
+        "nl": "getrouwd"
     },
     "divorced": {
         "level": {
             "A2": "OD",
             "B1": "EP"
         },
-        "en": "Divorced",
-        "fi": "Eronnut",
-        "nl": "Gescheiden"
+        "en": "divorced",
+        "fi": "eronnut",
+        "nl": "gescheiden"
     },
     "mother": {
         "level": {
@@ -136,14 +136,14 @@
             ]
         },
         "singular": {
-            "en": "Mother",
-            "fi": "Äiti",
-            "nl": "De moeder"
+            "en": "mother",
+            "fi": "äiti",
+            "nl": "de moeder"
         },
         "plural": {
-            "en": "Mothers",
-            "fi": "Äidit",
-            "nl": "De moeders"
+            "en": "mothers",
+            "fi": "äidit",
+            "nl": "de moeders"
         }
     },
     "father": {
@@ -155,14 +155,14 @@
             ]
         },
         "singular": {
-            "en": "Father",
-            "fi": "Isä",
-            "nl": "De vader"
+            "en": "father",
+            "fi": "isä",
+            "nl": "de vader"
         },
         "plural": {
-            "en": "Fathers",
-            "fi": "Isät",
-            "nl": "De vaders"
+            "en": "fathers",
+            "fi": "isät",
+            "nl": "de vaders"
         }
     },
     "child": {
@@ -174,14 +174,14 @@
             ]
         },
         "singular": {
-            "en": "Child",
-            "fi": "Lapsi",
-            "nl": "Het kind"
+            "en": "child",
+            "fi": "lapsi",
+            "nl": "het kind"
         },
         "plural": {
-            "en": "Children",
-            "fi": "Lapset",
-            "nl": "De kinderen"
+            "en": "children",
+            "fi": "lapset",
+            "nl": "de kinderen"
         }
     },
     "sister": {
@@ -192,14 +192,14 @@
             ]
         },
         "singular": {
-            "en": "Sister",
-            "fi": "Sisko",
-            "nl": "De zus"
+            "en": "sister",
+            "fi": "sisko",
+            "nl": "de zus"
         },
         "plural": {
-            "en": "Sisters",
-            "fi": "Siskot",
-            "nl": "De zussen"
+            "en": "sisters",
+            "fi": "siskot",
+            "nl": "de zussen"
         }
     },
     "brother": {
@@ -210,14 +210,14 @@
             ]
         },
         "singular": {
-            "en": "Brother",
-            "fi": "Veli",
-            "nl": "De broer"
+            "en": "brother",
+            "fi": "veli",
+            "nl": "de broer"
         },
         "plural": {
-            "en": "Brothers",
-            "fi": "Veljet",
-            "nl": "De broers"
+            "en": "brothers",
+            "fi": "veljet",
+            "nl": "de broers"
         }
     },
     "sibling": {
@@ -232,14 +232,14 @@
             ]
         },
         "singular": {
-            "en": "Sibling",
-            "fi": "Sisarus",
-            "nl": "De broer of zus|De zus of broer"
+            "en": "sibling",
+            "fi": "sisarus",
+            "nl": "(de broer of zus)"
         },
         "plural": {
             "en": "Siblings",
             "fi": "Sisarukset",
-            "nl": "De broers of zussen|De zussen of broers"
+            "nl": "(de broers en zussen)"
         }
     },
     "cousin": {
@@ -248,20 +248,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Cousin",
-            "fi": "Serkku",
-            "nl": [
-                "De neef",
-                "De nicht"
-            ]
+            "en": "cousin",
+            "fi": "serkku",
+            "nl": "(de neef of nicht)"
         },
         "plural": {
-            "en": "Cousins",
-            "fi": "Serkut",
-            "nl": [
-                "De neven",
-                "De nichten"
-            ]
+            "en": "cousins",
+            "fi": "serkut",
+            "nl": "(de neven en nichten)"
         }
     },
     "grandchild": {
@@ -278,14 +272,14 @@
             ]
         },
         "singular": {
-            "en": "Grandchild",
-            "fi": "Lapsenlapsi",
-            "nl": "Het kleinkind"
+            "en": "grandchild",
+            "fi": "lapsenlapsi",
+            "nl": "het kleinkind"
         },
         "plural": {
-            "en": "Grandchildren",
-            "fi": "Lapsenlapset",
-            "nl": "De kleinkinderen"
+            "en": "grandchildren",
+            "fi": "lapsenlapset",
+            "nl": "de kleinkinderen"
         }
     },
     "daughter": {
@@ -296,14 +290,14 @@
             ]
         },
         "singular": {
-            "en": "Daughter",
-            "fi": "Tytär",
-            "nl": "De dochter"
+            "en": "daughter",
+            "fi": "tytär",
+            "nl": "de dochter"
         },
         "plural": {
-            "en": "Daughters",
-            "fi": "Tyttäret",
-            "nl": "De dochters"
+            "en": "daughters",
+            "fi": "tyttäret",
+            "nl": "de dochters"
         }
     },
     "son": {
@@ -315,14 +309,14 @@
             ]
         },
         "singular": {
-            "en": "Son",
-            "fi": "Poika",
-            "nl": "De zoon"
+            "en": "son",
+            "fi": "poika",
+            "nl": "de zoon"
         },
         "plural": {
-            "en": "Sons",
-            "fi": "Pojat",
-            "nl": "De zonen"
+            "en": "sons",
+            "fi": "pojat",
+            "nl": "de zonen"
         }
     },
     "wife": {
@@ -334,14 +328,14 @@
             ]
         },
         "singular": {
-            "en": "Wife",
-            "fi": "Vaimo",
-            "nl": "De echtgenote"
+            "en": "wife",
+            "fi": "vaimo",
+            "nl": "de echtgenote"
         },
         "plural": {
-            "en": "Wives",
-            "fi": "Vaimot",
-            "nl": "De echtgenotes"
+            "en": "wives",
+            "fi": "vaimot",
+            "nl": "de echtgenotes"
         }
     },
     "husband": {
@@ -353,14 +347,14 @@
             ]
         },
         "singular": {
-            "en": "Husband",
-            "fi": "Aviomies|Mies",
-            "nl": "De echtgenoot"
+            "en": "husband",
+            "fi": "aviomies|mies",
+            "nl": "de echtgenoot"
         },
         "plural": {
-            "en": "Husbands",
-            "fi": "Aviomiehet|Miehet",
-            "nl": "De echtgenoten"
+            "en": "husbands",
+            "fi": "aviomiehet|miehet",
+            "nl": "de echtgenoten"
         }
     },
     "spouse": {
@@ -369,14 +363,14 @@
             "C2": "OD"
         },
         "singular": {
-            "en": "Spouse",
-            "fi": "Puoliso",
-            "nl": "De partner"
+            "en": "spouse",
+            "fi": "puoliso",
+            "nl": "de partner"
         },
         "plural": {
-            "en": "Spouses",
-            "fi": "Puolisot",
-            "nl": "De partners"
+            "en": "spouses",
+            "fi": "puolisot",
+            "nl": "de partners"
         }
     },
     "marriage": {
@@ -386,9 +380,9 @@
                 "OD"
             ]
         },
-        "en": "Marriage",
-        "fi": "Avioliitto",
-        "nl": "Het huwelijk"
+        "en": "marriage",
+        "fi": "avioliitto",
+        "nl": "het huwelijk"
     },
     "parent": {
         "level": {
@@ -403,14 +397,14 @@
             "nl": "old"
         },
         "singular": {
-            "en": "Parent",
-            "fi": "Vanhempi",
-            "nl": "De ouder"
+            "en": "parent",
+            "fi": "vanhempi;family",
+            "nl": "de ouder"
         },
         "plural": {
-            "en": "Parents",
-            "fi": "Vanhemmat",
-            "nl": "De ouders"
+            "en": "parents",
+            "fi": "vanhemmat",
+            "nl": "de ouders"
         }
     },
     "grandparent": {
@@ -430,14 +424,14 @@
             ]
         },
         "singular": {
-            "en": "Grandparent",
-            "fi": "Isovanhempi",
-            "nl": "De grootouder"
+            "en": "grandparent",
+            "fi": "isovanhempi",
+            "nl": "de grootouder"
         },
         "plural": {
-            "en": "Grandparents",
-            "fi": "Isovanhemmat",
-            "nl": "De grootouders"
+            "en": "grandparents",
+            "fi": "isovanhemmat",
+            "nl": "de grootouders"
         }
     },
     "parent-in-law": {
@@ -447,14 +441,14 @@
         },
         "roots": "parent",
         "singular": {
-            "en": "Parent-in-law",
-            "fi": "Appivanhempi",
-            "nl": "De schoonouder"
+            "en": "parent-in-law",
+            "fi": "appivanhempi",
+            "nl": "de schoonouder"
         },
         "plural": {
-            "en": "Parents-in-law",
-            "fi": "Appivanhemmat",
-            "nl": "De schoonouders"
+            "en": "parents-in-law",
+            "fi": "appivanhemmat",
+            "nl": "de schoonouders"
         }
     },
     "mother-in-law": {
@@ -464,14 +458,14 @@
         },
         "roots": "mother",
         "singular": {
-            "en": "Mother-in-law",
-            "fi": "Anoppi",
-            "nl": "De schoonmoeder"
+            "en": "mother-in-law",
+            "fi": "anoppi",
+            "nl": "de schoonmoeder"
         },
         "plural": {
-            "en": "Mothers-in-law",
-            "fi": "Anopit",
-            "nl": "De schoonmoeders"
+            "en": "mothers-in-law",
+            "fi": "anopit",
+            "nl": "de schoonmoeders"
         }
     },
     "father-in-law": {
@@ -481,14 +475,14 @@
         },
         "roots": "father",
         "singular": {
-            "en": "Father-in-law",
-            "fi": "Appiukko",
-            "nl": "De schoonvader"
+            "en": "father-in-law",
+            "fi": "appiukko",
+            "nl": "de schoonvader"
         },
         "plural": {
-            "en": "Fathers-in-law",
-            "fi": "Appiukot",
-            "nl": "De schoonvaders"
+            "en": "fathers-in-law",
+            "fi": "appiukot",
+            "nl": "de schoonvaders"
         }
     },
     "stepfather": {
@@ -500,14 +494,14 @@
         },
         "roots": "father",
         "singular": {
-            "en": "Stepfather",
-            "fi": "Isäpuoli",
-            "nl": "De stiefvader"
+            "en": "stepfather",
+            "fi": "isäpuoli",
+            "nl": "de stiefvader"
         },
         "plural": {
-            "en": "Stepfathers",
-            "fi": "Isäpuolet",
-            "nl": "De stiefvaders"
+            "en": "stepfathers",
+            "fi": "isäpuolet",
+            "nl": "de stiefvaders"
         }
     },
     "stepmother": {
@@ -519,14 +513,14 @@
         },
         "roots": "mother",
         "singular": {
-            "en": "Stepmother",
-            "fi": "Äitipuoli",
-            "nl": "De stiefmoeder"
+            "en": "stepmother",
+            "fi": "äitipuoli",
+            "nl": "de stiefmoeder"
         },
         "plural": {
-            "en": "Stepmothers",
-            "fi": "Äitipuolet",
-            "nl": "De stiefmoeders"
+            "en": "stepmothers",
+            "fi": "äitipuolet",
+            "nl": "de stiefmoeders"
         }
     },
     "they have x children and y grandchildren": {
diff --git a/src/topics/food.json b/src/topics/food.json
index c732aace..a462816e 100644
--- a/src/topics/food.json
+++ b/src/topics/food.json
@@ -8,13 +8,13 @@
             ]
         },
         "singular": {
-            "en": "Food",
-            "fi": "Ruoka",
-            "nl": "Het voedsel"
+            "en": "food",
+            "fi": "ruoka",
+            "nl": "het voedsel"
         },
         "plural": {
-            "en": "Foods",
-            "fi": "Ruoat"
+            "en": "foods",
+            "fi": "ruoat"
         }
     },
     "orange (fruit)": {
@@ -29,14 +29,14 @@
             "nl": "apple"
         },
         "singular": {
-            "en": "Orange",
-            "fi": "Appelsiini",
-            "nl": "De sinaasappel"
+            "en": "orange",
+            "fi": "appelsiini",
+            "nl": "de sinaasappel"
         },
         "plural": {
-            "en": "Oranges",
-            "fi": "Appelsiinit",
-            "nl": "De sinaasappels"
+            "en": "oranges",
+            "fi": "appelsiinit",
+            "nl": "de sinaasappels"
         }
     },
     "hotdog": {
@@ -52,17 +52,17 @@
         },
         "singular": {
             "en": [
-                "Hotdog|Hot dog"
+                "hotdog|hot dog"
             ],
-            "fi": "Hotdog",
-            "nl": "De hotdog"
+            "fi": "hotdog",
+            "nl": "de hotdog"
         },
         "plural": {
             "en": [
-                "Hotdogs|Hot dogs"
+                "hotdogs|hot dogs"
             ],
-            "fi": "Hotdogit",
-            "nl": "De hotdogs"
+            "fi": "hotdogit",
+            "nl": "de hotdogs"
         }
     },
     "cheese": {
@@ -73,14 +73,14 @@
             ]
         },
         "singular": {
-            "en": "Cheese",
-            "fi": "Juusto",
+            "en": "cheese",
+            "fi": "juusto",
             "nl": "De kaas"
         },
         "plural": {
-            "en": "Cheeses",
-            "fi": "Juustot",
-            "nl": "De kazen"
+            "en": "cheeses",
+            "fi": "juustot",
+            "nl": "de kazen"
         }
     },
     "coffee": {
@@ -92,14 +92,14 @@
             ]
         },
         "singular": {
-            "en": "Coffee",
-            "fi": "Kahvi",
-            "nl": "De koffie"
+            "en": "coffee",
+            "fi": "kahvi",
+            "nl": "de koffie"
         },
         "plural": {
-            "en": "Coffees",
-            "fi": "Kahvit",
-            "nl": "De koffies"
+            "en": "coffees",
+            "fi": "kahvit",
+            "nl": "de koffies"
         }
     },
     "fish": {
@@ -111,17 +111,17 @@
             ]
         },
         "singular": {
-            "en": "Fish",
-            "fi": "Kala",
-            "nl": "De vis"
+            "en": "fish",
+            "fi": "kala",
+            "nl": "de vis"
         },
         "plural": {
             "en": [
-                "Fish",
-                "Fishes"
+                "fish",
+                "fishes"
             ],
-            "fi": "Kalat",
-            "nl": "De vissen"
+            "fi": "kalat",
+            "nl": "de vissen"
         }
     },
     "chicken": {
@@ -130,14 +130,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Chicken",
-            "fi": "Kana",
-            "nl": "De kip"
+            "en": "chicken",
+            "fi": "kana",
+            "nl": "de kip"
         },
         "plural": {
-            "en": "Chickens",
-            "fi": "Kanat",
-            "nl": "De kippen"
+            "en": "chickens",
+            "fi": "kanat",
+            "nl": "de kippen"
         }
     },
     "dressing": {
@@ -146,14 +146,14 @@
             "none": "EP"
         },
         "singular": {
-            "en": "Dressing",
-            "fi": "Kastike",
-            "nl": "De dressing"
+            "en": "dressing",
+            "fi": "kastike",
+            "nl": "de dressing"
         },
         "plural": {
-            "en": "Dressings",
-            "fi": "Kastikkeet",
-            "nl": "De dressings"
+            "en": "dressings",
+            "fi": "kastikkeet",
+            "nl": "de dressings"
         }
     },
     "ketchup": {
@@ -162,13 +162,13 @@
             "none": "EP"
         },
         "singular": {
-            "en": "Ketchup",
-            "fi": "Ketsuppi",
-            "nl": "De ketchup"
+            "en": "ketchup",
+            "fi": "ketsuppi",
+            "nl": "de ketchup"
         },
         "plural": {
-            "en": "Ketchups",
-            "fi": "Ketsupit"
+            "en": "ketchups",
+            "fi": "ketsupit"
         }
     },
     "bread": {
@@ -179,14 +179,14 @@
             ]
         },
         "singular": {
-            "en": "Bread",
-            "fi": "Leipä",
-            "nl": "Het brood"
+            "en": "bread",
+            "fi": "leipä",
+            "nl": "het brood"
         },
         "plural": {
-            "en": "Breads",
-            "fi": "Leivät",
-            "nl": "De broden"
+            "en": "breads",
+            "fi": "leivät",
+            "nl": "de broden"
         }
     },
     "meat": {
@@ -197,14 +197,14 @@
             ]
         },
         "singular": {
-            "en": "Meat",
-            "fi": "Liha",
-            "nl": "Het vlees"
+            "en": "meat",
+            "fi": "liha",
+            "nl": "het vlees"
         },
         "plural": {
-            "en": "Meats",
-            "fi": "Lihat",
-            "nl": "De vlezen"
+            "en": "meats",
+            "fi": "lihat",
+            "nl": "de vlezen"
         }
     },
     "milk": {
@@ -215,13 +215,13 @@
             ]
         },
         "singular": {
-            "en": "Milk",
-            "fi": "Maito",
-            "nl": "De melk"
+            "en": "milk",
+            "fi": "maito",
+            "nl": "de melk"
         },
         "plural": {
-            "en": "Milks",
-            "fi": "Maidot"
+            "en": "milks",
+            "fi": "maidot"
         }
     },
     "sausage": {
@@ -232,26 +232,26 @@
             ]
         },
         "singular": {
-            "en": "Sausage",
-            "fi": "Makkara",
-            "nl": "De worst"
+            "en": "sausage",
+            "fi": "makkara",
+            "nl": "de worst"
         },
         "plural": {
-            "en": "Sausages",
-            "fi": "Makkarat",
-            "nl": "De worsten"
+            "en": "sausages",
+            "fi": "makkarat",
+            "nl": "de worsten"
         }
     },
     "mämmi": {
         "singular": {
-            "en": "(Traditional Finnish Easter dessert)",
-            "fi": "Mämmi",
-            "nl": "(Traditioneel Fins paasdessert)"
+            "en": "(traditional Finnish Easter dessert)",
+            "fi": "mämmi",
+            "nl": "(traditioneel Fins paasdessert)"
         },
         "plural": {
-            "en": "(Traditional Finnish Easter desserts)",
-            "fi": "Mämmit",
-            "nl": "(Traditionele Finse paasdesserts)"
+            "en": "(traditional Finnish Easter desserts)",
+            "fi": "mämmit",
+            "nl": "(traditionele Finse paasdesserts)"
         }
     },
     "strawberry": {
@@ -260,14 +260,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Strawberry",
-            "fi": "Mansikka",
-            "nl": "De aardbei"
+            "en": "strawberry",
+            "fi": "mansikka",
+            "nl": "de aardbei"
         },
         "plural": {
-            "en": "Strawberries",
-            "fi": "Mansikat",
-            "nl": "De aardbeien"
+            "en": "strawberries",
+            "fi": "mansikat",
+            "nl": "de aardbeien"
         }
     },
     "spice": {
@@ -276,14 +276,14 @@
             "B2": "OD"
         },
         "singular": {
-            "en": "Spice",
-            "fi": "Mauste",
+            "en": "spice",
+            "fi": "mauste",
             "nl": "het kruid"
         },
         "plural": {
-            "en": "Spices",
-            "fi": "Mausteet",
-            "nl": "De kruiden"
+            "en": "spices",
+            "fi": "mausteet",
+            "nl": "de kruiden"
         }
     },
     "juice": {
@@ -294,14 +294,14 @@
             ]
         },
         "singular": {
-            "en": "Juice",
-            "fi": "Mehu",
-            "nl": "Het sap"
+            "en": "juice",
+            "fi": "mehu",
+            "nl": "het sap"
         },
         "plural": {
-            "en": "Juices",
-            "fi": "Mehut",
-            "nl": "De sappen"
+            "en": "juices",
+            "fi": "mehut",
+            "nl": "de sappen"
         }
     },
     "apple": {
@@ -312,14 +312,14 @@
             ]
         },
         "singular": {
-            "en": "Apple",
-            "fi": "Omena",
-            "nl": "De appel"
+            "en": "apple",
+            "fi": "omena",
+            "nl": "de appel"
         },
         "plural": {
-            "en": "Apples",
-            "fi": "Omenat",
-            "nl": "De appels"
+            "en": "apples",
+            "fi": "omenat",
+            "nl": "de appels"
         }
     },
     "potato": {
@@ -333,14 +333,14 @@
             "nl": "apple"
         },
         "singular": {
-            "en": "Potato",
-            "fi": "Peruna",
-            "nl": "De aardappel"
+            "en": "potato",
+            "fi": "peruna",
+            "nl": "de aardappel"
         },
         "plural": {
-            "en": "Potatoes",
-            "fi": "Perunat",
-            "nl": "De aardappels"
+            "en": "potatoes",
+            "fi": "perunat",
+            "nl": "de aardappels"
         }
     },
     "steak": {
@@ -349,14 +349,14 @@
             "B1": "OD"
         },
         "singular": {
-            "en": "Steak",
-            "fi": "Pihvi",
-            "nl": "De steak"
+            "en": "steak",
+            "fi": "pihvi",
+            "nl": "de steak"
         },
         "plural": {
-            "en": "Steaks",
-            "fi": "Pihvit",
-            "nl": "De steaks"
+            "en": "steaks",
+            "fi": "pihvit",
+            "nl": "de steaks"
         }
     },
     "pepper": {
@@ -365,14 +365,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Pepper",
-            "fi": "Pippuri",
-            "nl": "De peper"
+            "en": "pepper",
+            "fi": "pippuri",
+            "nl": "de peper"
         },
         "plural": {
-            "en": "Peppers",
-            "fi": "Pippurit",
-            "nl": "De pepers"
+            "en": "peppers",
+            "fi": "pippurit",
+            "nl": "de pepers"
         }
     },
     "salad": {
@@ -381,14 +381,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Salad",
-            "fi": "Salaatti",
-            "nl": "De salade"
+            "en": "salad",
+            "fi": "salaatti",
+            "nl": "de salade"
         },
         "plural": {
-            "en": "Salads",
-            "fi": "Salaatit",
-            "nl": "De salades"
+            "en": "salads",
+            "fi": "salaatit",
+            "nl": "de salades"
         }
     },
     "mustard": {
@@ -397,14 +397,14 @@
             "C2": "OD"
         },
         "singular": {
-            "en": "Mustard",
-            "fi": "Sinappi",
-            "nl": "De mosterd"
+            "en": "mustard",
+            "fi": "sinappi",
+            "nl": "de mosterd"
         },
         "plural": {
-            "en": "Mustards",
-            "fi": "Sinapit",
-            "nl": "De mosterds"
+            "en": "mustards",
+            "fi": "sinapit",
+            "nl": "de mosterds"
         }
     },
     "onion": {
@@ -413,14 +413,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Onion",
-            "fi": "Sipuli",
-            "nl": "De ui"
+            "en": "onion",
+            "fi": "sipuli",
+            "nl": "de ui"
         },
         "plural": {
-            "en": "Onions",
-            "fi": "Sipulit",
-            "nl": "De uien"
+            "en": "onions",
+            "fi": "sipulit",
+            "nl": "de uien"
         }
     },
     "lemon": {
@@ -432,13 +432,13 @@
         },
         "singular": {
             "en": "Lemon",
-            "fi": "Sitruuna",
-            "nl": "De citroen"
+            "fi": "sitruuna",
+            "nl": "de citroen"
         },
         "plural": {
-            "en": "Lemons",
-            "fi": "Sitruunat",
-            "nl": "De citroenen"
+            "en": "lemons",
+            "fi": "sitruunat",
+            "nl": "de citroenen"
         }
     },
     "sugar": {
@@ -449,14 +449,14 @@
             ]
         },
         "singular": {
-            "en": "Sugar",
-            "fi": "Sokeri",
-            "nl": "De suiker"
+            "en": "sugar",
+            "fi": "sokeri",
+            "nl": "de suiker"
         },
         "plural": {
-            "en": "Sugars",
-            "fi": "Sokerit",
-            "nl": "De suikers"
+            "en": "sugars",
+            "fi": "sokerit",
+            "nl": "de suikers"
         }
     },
     "salt": {
@@ -467,14 +467,14 @@
             ]
         },
         "singular": {
-            "en": "Salt",
-            "fi": "Suola",
-            "nl": "Het zout"
+            "en": "salt",
+            "fi": "suola",
+            "nl": "het zout"
         },
         "plural": {
-            "en": "Salts",
-            "fi": "Suolat",
-            "nl": "De zouten"
+            "en": "salts",
+            "fi": "suolat",
+            "nl": "de zouten"
         }
     },
     "tomato": {
@@ -485,14 +485,14 @@
             ]
         },
         "singular": {
-            "en": "Tomato",
-            "fi": "Tomaatti",
-            "nl": "De tomaat"
+            "en": "tomato",
+            "fi": "tomaatti",
+            "nl": "de tomaat"
         },
         "plural": {
-            "en": "Tomatoes",
-            "fi": "Tomaatit",
-            "nl": "De tomaten"
+            "en": "tomatoes",
+            "fi": "tomaatit",
+            "nl": "de tomaten"
         }
     },
     "water": {
@@ -504,16 +504,16 @@
             ]
         },
         "singular": {
-            "en": "Water",
-            "fi": "Vesi",
-            "nl": "Het water"
+            "en": "water",
+            "fi": "vesi",
+            "nl": "het water"
         },
         "plural": {
-            "en": "Waters",
-            "fi": "Vedet",
+            "en": "waters",
+            "fi": "vedet",
             "nl": [
-                "De waters",
-                "De wateren"
+                "de waters",
+                "de wateren"
             ]
         }
     },
@@ -528,14 +528,14 @@
             "fi": "bread"
         },
         "singular": {
-            "en": "Sandwich",
-            "fi": "Voileipä",
-            "nl": "De boterham"
+            "en": "sandwich",
+            "fi": "voileipä",
+            "nl": "de boterham"
         },
         "plural": {
-            "en": "Sandwiches",
-            "fi": "Voileivät",
-            "nl": "De boterhammen"
+            "en": "sandwiches",
+            "fi": "voileivät",
+            "nl": "de boterhammen"
         }
     },
     "nut": {
@@ -544,14 +544,14 @@
             "B2": "EP"
         },
         "singular": {
-            "en": "Nut",
-            "fi": "Pähkinä",
-            "nl": "De noot"
+            "en": "nut",
+            "fi": "pähkinä",
+            "nl": "de noot"
         },
         "plural": {
-            "en": "Nuts",
-            "fi": "Pähkinät",
-            "nl": "De noten"
+            "en": "nuts",
+            "fi": "pähkinät",
+            "nl": "de noten"
         }
     },
     "cherry": {
@@ -562,14 +562,14 @@
             ]
         },
         "singular": {
-            "en": "Cherry",
-            "fi": "Kirsikka",
-            "nl": "De kers"
+            "en": "cherry",
+            "fi": "kirsikka",
+            "nl": "de kers"
         },
         "plural": {
-            "en": "Cherries",
-            "fi": "Kirsikat",
-            "nl": "De kersen"
+            "en": "cherries",
+            "fi": "kirsikat",
+            "nl": "de kersen"
         }
     },
     "pear": {
@@ -578,14 +578,14 @@
             "B1": "OD"
         },
         "singular": {
-            "en": "Pear",
-            "fi": "Päärynä",
-            "nl": "De peer"
+            "en": "pear",
+            "fi": "päärynä",
+            "nl": "de peer"
         },
         "plural": {
-            "en": "Pears",
-            "fi": "Päärynät",
-            "nl": "De peren"
+            "en": "pears",
+            "fi": "päärynät",
+            "nl": "de peren"
         }
     },
     "cauliflower": {
@@ -595,14 +595,14 @@
         },
         "roots": "flower",
         "singular": {
-            "en": "Cauliflower",
-            "fi": "Kukkakaali",
-            "nl": "De bloemkool"
+            "en": "cauliflower",
+            "fi": "kukkakaali",
+            "nl": "de bloemkool"
         },
         "plural": {
-            "en": "Cauliflowers",
-            "fi": "Kukkakaalit",
-            "nl": "De bloemkolen"
+            "en": "cauliflowers",
+            "fi": "kukkakaalit",
+            "nl": "de bloemkolen"
         }
     },
     "mushroom": {
@@ -616,14 +616,14 @@
             "nl": "chair"
         },
         "singular": {
-            "en": "Mushroom",
-            "fi": "Sieni",
-            "nl": "De paddenstoel"
+            "en": "mushroom",
+            "fi": "sieni",
+            "nl": "de paddenstoel"
         },
         "plural": {
-            "en": "Mushrooms",
-            "fi": "Sienet",
-            "nl": "De paddenstoelen"
+            "en": "mushrooms",
+            "fi": "sienet",
+            "nl": "de paddenstoelen"
         }
     },
     "garlic": {
@@ -638,14 +638,14 @@
             ]
         },
         "singular": {
-            "en": "Garlic",
-            "fi": "Valkosipuli",
-            "nl": "De knoflook"
+            "en": "garlic",
+            "fi": "valkosipuli",
+            "nl": "de knoflook"
         },
         "plural": {
-            "en": "Garlics",
-            "fi": "Valkosipulit",
-            "nl": "De knofloken"
+            "en": "garlics",
+            "fi": "valkosipulit",
+            "nl": "de knofloken"
         }
     },
     "bean": {
@@ -656,14 +656,14 @@
             ]
         },
         "singular": {
-            "en": "Bean",
-            "fi": "Papu",
-            "nl": "De boon"
+            "en": "bean",
+            "fi": "papu",
+            "nl": "de boon"
         },
         "plural": {
-            "en": "Beans",
-            "fi": "Pavut",
-            "nl": "De bonen"
+            "en": "beans",
+            "fi": "pavut",
+            "nl": "de bonen"
         }
     },
     "cookie": {
@@ -672,14 +672,14 @@
             "none": "EP"
         },
         "singular": {
-            "en": "Cookie",
-            "fi": "Keksi",
-            "nl": "Het koekje"
+            "en": "cookie",
+            "fi": "keksi",
+            "nl": "het koekje"
         },
         "plural": {
-            "en": "Cookies",
-            "fi": "Keksit",
-            "nl": "De koekjes"
+            "en": "cookies",
+            "fi": "keksit",
+            "nl": "de koekjes"
         }
     },
     "cake": {
@@ -690,14 +690,14 @@
             ]
         },
         "singular": {
-            "en": "Cake",
-            "fi": "Kakku",
-            "nl": "De taart"
+            "en": "cake",
+            "fi": "kakku",
+            "nl": "de taart"
         },
         "plural": {
-            "en": "Cakes",
-            "fi": "Kakut",
-            "nl": "De taarten"
+            "en": "cakes",
+            "fi": "kakut",
+            "nl": "de taarten"
         }
     },
     "cream": {
@@ -707,9 +707,9 @@
                 "OD"
             ]
         },
-        "en": "Cream",
-        "fi": "Kerma",
-        "nl": "De room"
+        "en": "cream",
+        "fi": "kerma",
+        "nl": "de room"
     },
     "whipped cream": {
         "level": {
@@ -717,9 +717,9 @@
             "none": "EP"
         },
         "roots": "cream",
-        "en": "Whipped cream",
-        "fi": "Kermavaahto",
-        "nl": "De slagroom"
+        "en": "whipped cream",
+        "fi": "kermavaahto",
+        "nl": "de slagroom"
     },
     "ice cream": {
         "level": {
@@ -737,14 +737,14 @@
             "nl": "ice"
         },
         "singular": {
-            "en": "Ice cream",
-            "fi": "Jäätelö",
-            "nl": "Het ijsje|Het ijs"
+            "en": "ice cream",
+            "fi": "jäätelö",
+            "nl": "het ijsje|het ijs"
         },
         "plural": {
-            "en": "Ice creams",
-            "fi": "Jäätelöt",
-            "nl": "De ijsjes"
+            "en": "ice creams",
+            "fi": "jäätelöt",
+            "nl": "de ijsjes"
         }
     },
     "banana": {
@@ -755,14 +755,14 @@
             ]
         },
         "singular": {
-            "en": "Banana",
-            "fi": "Banaani",
-            "nl": "De banaan"
+            "en": "banana",
+            "fi": "banaani",
+            "nl": "de banaan"
         },
         "plural": {
-            "en": "Bananas",
-            "fi": "Banaanit",
-            "nl": "De bananen"
+            "en": "bananas",
+            "fi": "banaanit",
+            "nl": "de bananen"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/furniture.json b/src/topics/furniture.json
index 0893e7fc..9f85f416 100644
--- a/src/topics/furniture.json
+++ b/src/topics/furniture.json
@@ -8,14 +8,14 @@
             ]
         },
         "singular": {
-            "en": "Table",
-            "fi": "Pöytä",
-            "nl": "De tafel"
+            "en": "table",
+            "fi": "pöytä",
+            "nl": "de tafel"
         },
         "plural": {
-            "en": "Tables",
-            "fi": "Pöydät",
-            "nl": "De tafels"
+            "en": "tables",
+            "fi": "pöydät",
+            "nl": "de tafels"
         }
     },
     "bed": {
@@ -26,14 +26,14 @@
             ]
         },
         "singular": {
-            "en": "Bed",
-            "fi": "Sänky",
-            "nl": "Het bed"
+            "en": "bed",
+            "fi": "sänky",
+            "nl": "het bed"
         },
         "plural": {
-            "en": "Beds",
-            "fi": "Sängyt",
-            "nl": "De bedden"
+            "en": "beds",
+            "fi": "sängyt",
+            "nl": "de bedden"
         }
     },
     "sofa": {
@@ -42,14 +42,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Sofa",
-            "fi": "Sohva",
-            "nl": "De sofa"
+            "en": "sofa",
+            "fi": "sohva",
+            "nl": "de sofa"
         },
         "plural": {
-            "en": "Sofas",
-            "fi": "Sohvat",
-            "nl": "De sofa's"
+            "en": "sofas",
+            "fi": "sohvat",
+            "nl": "de sofa's"
         }
     },
     "pillow": {
@@ -58,14 +58,14 @@
             "none": "OD"
         },
         "singular": {
-            "en": "Pillow",
-            "fi": "Tyyny",
-            "nl": "Het kussen"
+            "en": "pillow",
+            "fi": "tyyny",
+            "nl": "het kussen"
         },
         "plural": {
-            "en": "Pillows",
-            "fi": "Tyynyt",
-            "nl": "De kussens"
+            "en": "pillows",
+            "fi": "tyynyt",
+            "nl": "de kussens"
         }
     },
     "chair": {
@@ -76,14 +76,14 @@
             ]
         },
         "singular": {
-            "en": "Chair",
-            "fi": "Tuoli",
-            "nl": "De stoel"
+            "en": "chair",
+            "fi": "tuoli",
+            "nl": "de stoel"
         },
         "plural": {
-            "en": "Chairs",
-            "fi": "Tuolit",
-            "nl": "De stoelen"
+            "en": "chairs",
+            "fi": "tuolit",
+            "nl": "de stoelen"
         }
     },
     "desk": {
@@ -100,20 +100,20 @@
             ]
         },
         "singular": {
-            "en": "Desk",
+            "en": "desk",
             "fi": [
-                "Työpöytä",
-                "Kirjoituspöytä"
+                "työpöytä",
+                "kirjoituspöytä"
             ],
-            "nl": "Het bureau"
+            "nl": "het bureau"
         },
         "plural": {
-            "en": "Desks",
+            "en": "desks",
             "fi": [
-                "Työpöydät",
-                "Kirjoituspöydät"
+                "työpöydät",
+                "kirjoituspöydät"
             ],
-            "nl": "De bureaus"
+            "nl": "de bureaus"
         }
     },
     "lamp": {
@@ -124,14 +124,14 @@
             ]
         },
         "singular": {
-            "en": "Lamp",
-            "fi": "Lamppu",
-            "nl": "De lamp"
+            "en": "lamp",
+            "fi": "lamppu",
+            "nl": "de lamp"
         },
         "plural": {
-            "en": "Lamps",
-            "fi": "Lamput",
-            "nl": "De lampen"
+            "en": "lamps",
+            "fi": "lamput",
+            "nl": "de lampen"
         }
     },
     "curtain": {
@@ -140,14 +140,14 @@
             "B1": "OD"
         },
         "singular": {
-            "en": "Curtain",
-            "fi": "Verho",
-            "nl": "Het gordijn"
+            "en": "curtain",
+            "fi": "verho",
+            "nl": "het gordijn"
         },
         "plural": {
-            "en": "Curtains",
-            "fi": "Verhot",
-            "nl": "De gordijnen"
+            "en": "curtains",
+            "fi": "verhot",
+            "nl": "de gordijnen"
         }
     },
     "carpet": {
@@ -158,14 +158,14 @@
             ]
         },
         "singular": {
-            "en": "Carpet",
-            "fi": "Matto",
-            "nl": "Het tapijt"
+            "en": "carpet",
+            "fi": "matto",
+            "nl": "het tapijt"
         },
         "plural": {
-            "en": "Carpets",
-            "fi": "Matot",
-            "nl": "De tapijten"
+            "en": "carpets",
+            "fi": "matot",
+            "nl": "de tapijten"
         }
     },
     "the door is locked": {
diff --git a/src/topics/greetings.json b/src/topics/greetings.json
index c519f112..1eb2d787 100644
--- a/src/topics/greetings.json
+++ b/src/topics/greetings.json
@@ -94,14 +94,14 @@
             ]
         },
         "singular": {
-            "en": "Name",
-            "fi": "Nimi",
-            "nl": "De naam"
+            "en": "name",
+            "fi": "nimi",
+            "nl": "de naam"
         },
         "plural": {
-            "en": "Names",
-            "fi": "Nimet",
-            "nl": "De namen"
+            "en": "names",
+            "fi": "nimet",
+            "nl": "de namen"
         }
     },
     "what is your name": {
diff --git a/src/topics/health.json b/src/topics/health.json
index 1ef52c14..93b37622 100644
--- a/src/topics/health.json
+++ b/src/topics/health.json
@@ -4,18 +4,18 @@
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "Health",
-        "fi": "Terveys",
-        "nl": "De gezondheid"
+        "en": "health",
+        "fi": "terveys",
+        "nl": "de gezondheid"
     },
     "care": {
         "level": {
             "A2": "OD",
             "B2": "EP"
         },
-        "en": "Care",
-        "fi": "Hoito",
-        "nl": "De zorg"
+        "en": "care",
+        "fi": "hoito",
+        "nl": "de zorg"
     },
     "health care": {
         "level": {
@@ -26,9 +26,9 @@
             "health",
             "care"
         ],
-        "en": "Health care",
-        "fi": "Terveydenhoito",
-        "nl": "De gezondheidszorg"
+        "en": "health care",
+        "fi": "terveydenhoito",
+        "nl": "de gezondheidszorg"
     },
     "disease": {
         "level": {
@@ -36,14 +36,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Disease",
-            "fi": "Sairaus",
-            "nl": "De ziekte"
+            "en": "disease",
+            "fi": "sairaus",
+            "nl": "de ziekte"
         },
         "plural": {
-            "en": "Diseases",
-            "fi": "Sairaudet",
-            "nl": "De ziektes;De ziekten"
+            "en": "diseases",
+            "fi": "sairaudet",
+            "nl": "de ziektes|de ziekten"
         }
     },
     "patient": {
@@ -52,14 +52,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Patient",
-            "fi": "Potilas",
-            "nl": "De patiënt"
+            "en": "patient",
+            "fi": "potilas",
+            "nl": "de patiënt"
         },
         "plural": {
-            "en": "Patients",
-            "fi": "Potilaat",
-            "nl": "De patiënten"
+            "en": "patients",
+            "fi": "potilaat",
+            "nl": "de patiënten"
         }
     },
     "medicine": {
@@ -70,14 +70,14 @@
             ]
         },
         "singular": {
-            "en": "Medicine",
-            "fi": "Lääke",
-            "nl": "Het medicijn"
+            "en": "medicine",
+            "fi": "lääke",
+            "nl": "het medicijn"
         },
         "plural": {
-            "en": "Medicines",
-            "fi": "Lääkkeet",
-            "nl": "De medicijnen"
+            "en": "medicines",
+            "fi": "lääkkeet",
+            "nl": "de medicijnen"
         }
     },
     "wound": {
@@ -88,14 +88,14 @@
             ]
         },
         "singular": {
-            "en": "Wound",
-            "fi": "Haava",
-            "nl": "De wond"
+            "en": "wound",
+            "fi": "haava",
+            "nl": "de wond"
         },
         "plural": {
-            "en": "Wounds",
-            "fi": "Haavat",
-            "nl": "De wonden"
+            "en": "wounds",
+            "fi": "haavat",
+            "nl": "de wonden"
         }
     },
     "flu": {
@@ -104,14 +104,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Flu",
-            "fi": "Flunssa",
-            "nl": "De griep"
+            "en": "flu",
+            "fi": "flunssa",
+            "nl": "de griep"
         },
         "plural": {
-            "en": "Flus",
-            "fi": "Flunssat",
-            "nl": "De griepen"
+            "en": "flus",
+            "fi": "flunssat",
+            "nl": "de griepen"
         }
     },
     "fever": {
@@ -120,14 +120,14 @@
             "B2": "OD"
         },
         "singular": {
-            "en": "Fever",
-            "fi": "Kuume",
-            "nl": "De koorts"
+            "en": "fever",
+            "fi": "kuume",
+            "nl": "de koorts"
         },
         "plural": {
-            "en": "Fevers",
-            "fi": "Kuumeet",
-            "nl": "Koortsen"
+            "en": "fevers",
+            "fi": "kuumeet",
+            "nl": "koortsen"
         }
     },
     "blood": {
@@ -138,13 +138,13 @@
             ]
         },
         "singular": {
-            "en": "Blood",
-            "fi": "Veri",
-            "nl": "Het bloed"
+            "en": "blood",
+            "fi": "veri",
+            "nl": "het bloed"
         },
         "plural": {
-            "en": "Bloods",
-            "fi": "Veret"
+            "en": "bloods",
+            "fi": "veret"
         }
     },
     "ache": {
@@ -153,14 +153,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Ache",
-            "fi": "Särky",
-            "nl": "De pijn;dull"
+            "en": "ache",
+            "fi": "särky",
+            "nl": "de pijn;dull"
         },
         "plural": {
-            "en": "Aches",
-            "fi": "Säryt",
-            "nl": "De pijnen;dull"
+            "en": "aches",
+            "fi": "säryt",
+            "nl": "de pijnen;dull"
         }
     },
     "pain": {
@@ -171,14 +171,14 @@
             ]
         },
         "singular": {
-            "en": "Pain",
-            "fi": "Kipu",
-            "nl": "De pijn;sharp"
+            "en": "pain",
+            "fi": "kipu",
+            "nl": "de pijn;sharp"
         },
         "plural": {
-            "en": "Pains",
-            "fi": "Kivut",
-            "nl": "De pijnen;sharp"
+            "en": "pains",
+            "fi": "kivut",
+            "nl": "de pijnen;sharp"
         }
     },
     "headache": {
@@ -193,14 +193,14 @@
             "ache"
         ],
         "singular": {
-            "en": "Headache",
-            "fi": "Päänsärky",
-            "nl": "De hoofdpijn"
+            "en": "headache",
+            "fi": "päänsärky",
+            "nl": "de hoofdpijn"
         },
         "plural": {
-            "en": "Headaches",
-            "fi": "Päänsäryt",
-            "nl": "De hoofdpijnen"
+            "en": "headaches",
+            "fi": "päänsäryt",
+            "nl": "de hoofdpijnen"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/holidays.json b/src/topics/holidays.json
index 094f52d7..bdb257ba 100644
--- a/src/topics/holidays.json
+++ b/src/topics/holidays.json
@@ -8,14 +8,14 @@
         },
         "roots": "day",
         "singular": {
-            "en": "Holiday",
-            "fi": "Juhlapäivä",
-            "nl": "De feestdag"
+            "en": "holiday",
+            "fi": "juhlapäivä",
+            "nl": "de feestdag"
         },
         "plural": {
-            "en": "Holidays",
-            "fi": "Juhlapäivät",
-            "nl": "De feestdagen"
+            "en": "holidays",
+            "fi": "juhlapäivät",
+            "nl": "de feestdagen"
         }
     },
     "christmas": {
@@ -42,7 +42,7 @@
         },
         "en": "Christmas Eve",
         "fi": "Jouluaatto",
-        "nl": "Kerstavond"
+        "nl": "kerstavond"
     },
     "christmas day": {
         "level": {
@@ -55,7 +55,7 @@
         ],
         "en": "Christmas Day",
         "fi": "Joulupäivä",
-        "nl": "Eerste kerstdag"
+        "nl": "eerste kerstdag"
     },
     "boxing day": {
         "level": {
@@ -72,7 +72,7 @@
         },
         "en": "Boxing Day",
         "fi": "Tapaninpäivä",
-        "nl": "Tweede kerstdag"
+        "nl": "tweede kerstdag"
     },
     "merry christmas": {
         "level": {
@@ -105,8 +105,8 @@
             "tree"
         ],
         "en": "Christmas tree",
-        "fi": "Joulukuusi",
-        "nl": "De kerstboom"
+        "fi": "joulukuusi",
+        "nl": "de kerstboom"
     },
     "santa": {
         "level": {
@@ -120,8 +120,8 @@
             "nl": "christmas"
         },
         "en": "Santa Claus|Santa",
-        "fi": "Joulupukki",
-        "nl": "De kerstman"
+        "fi": "joulupukki",
+        "nl": "de kerstman"
     },
     "elf": {
         "level": {
@@ -130,14 +130,14 @@
                 "OD"
             ]
         },
-        "en": "Elf",
-        "fi": "Tonttu",
-        "nl": "De elf"
+        "en": "elf",
+        "fi": "tonttu",
+        "nl": "de elf"
     },
     "angel": {
-        "en": "Angel",
-        "fi": "Enkeli",
-        "nl": "De engel"
+        "en": "angel",
+        "fi": "enkeli",
+        "nl": "de engel"
     },
     "bauble": {
         "level": {
@@ -153,9 +153,9 @@
             ],
             "nl": "christmas"
         },
-        "en": "Bauble",
-        "fi": "Joulukuusenpallo|Joulupallo",
-        "nl": "De kerstbal"
+        "en": "bauble",
+        "fi": "joulukuusenpallo|joulupallo",
+        "nl": "de kerstbal"
     },
     "new year": {
         "level": {
@@ -250,9 +250,9 @@
             "en": "summer",
             "nl": "summer"
         },
-        "en": "Midsummer",
-        "fi": "Juhannus",
-        "nl": "Midzomer"
+        "en": "midsummer",
+        "fi": "juhannus",
+        "nl": "midzomer"
     },
     "finnish independence day": {
         "level": {
diff --git a/src/topics/house.json b/src/topics/house.json
index cf127726..63888848 100644
--- a/src/topics/house.json
+++ b/src/topics/house.json
@@ -5,14 +5,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Apartment",
-            "fi": "Asunto",
-            "nl": "Het appartement"
+            "en": "apartment",
+            "fi": "asunto",
+            "nl": "het appartement"
         },
         "plural": {
-            "en": "Apartments",
-            "fi": "Asunnot",
-            "nl": "De appartementen"
+            "en": "apartments",
+            "fi": "asunnot",
+            "nl": "de appartementen"
         }
     },
     "room": {
@@ -24,14 +24,14 @@
             ]
         },
         "singular": {
-            "en": "Room",
-            "fi": "Huone",
-            "nl": "De kamer"
+            "en": "room",
+            "fi": "huone",
+            "nl": "de kamer"
         },
         "plural": {
-            "en": "Rooms",
-            "fi": "Huoneet",
-            "nl": "De kamers"
+            "en": "rooms",
+            "fi": "huoneet",
+            "nl": "de kamers"
         }
     },
     "basement": {
@@ -42,14 +42,14 @@
             ]
         },
         "singular": {
-            "en": "Basement",
-            "fi": "Kellari",
-            "nl": "De kelder"
+            "en": "basement",
+            "fi": "kellari",
+            "nl": "de kelder"
         },
         "plural": {
-            "en": "Basements",
-            "fi": "Kellarit",
-            "nl": "De kelders"
+            "en": "basements",
+            "fi": "kellarit",
+            "nl": "de kelders"
         }
     },
     "home": {
@@ -61,13 +61,13 @@
             ]
         },
         "singular": {
-            "en": "Home",
-            "fi": "Koti",
-            "nl": "Het thuis"
+            "en": "home",
+            "fi": "koti",
+            "nl": "het thuis"
         },
         "plural": {
-            "en": "Homes",
-            "fi": "Kodit"
+            "en": "homes",
+            "fi": "kodit"
         }
     },
     "garden": {
@@ -79,14 +79,14 @@
             ]
         },
         "singular": {
-            "en": "Garden",
-            "fi": "Piha",
-            "nl": "De tuin"
+            "en": "garden",
+            "fi": "piha",
+            "nl": "de tuin"
         },
         "plural": {
-            "en": "Gardens",
-            "fi": "Pihat",
-            "nl": "De tuinen"
+            "en": "gardens",
+            "fi": "pihat",
+            "nl": "de tuinen"
         }
     },
     "house": {
@@ -98,14 +98,14 @@
             ]
         },
         "singular": {
-            "en": "House",
-            "fi": "Talo",
-            "nl": "Het huis"
+            "en": "house",
+            "fi": "talo",
+            "nl": "het huis"
         },
         "plural": {
-            "en": "Houses",
-            "fi": "Talot",
-            "nl": "De huizen"
+            "en": "houses",
+            "fi": "talot",
+            "nl": "de huizen"
         }
     },
     "veranda": {
@@ -114,14 +114,14 @@
             "none": "EP"
         },
         "singular": {
-            "en": "Veranda",
-            "fi": "Veranta",
-            "nl": "De veranda"
+            "en": "veranda",
+            "fi": "veranta",
+            "nl": "de veranda"
         },
         "plural": {
-            "en": "Verandas",
-            "fi": "Verannat",
-            "nl": "De veranda's"
+            "en": "verandas",
+            "fi": "verannat",
+            "nl": "de veranda's"
         }
     },
     "barbecue": {
@@ -130,14 +130,14 @@
             "B1": "OD"
         },
         "singular": {
-            "en": "Barbecue",
-            "fi": "Grilli",
-            "nl": "De barbecue"
+            "en": "barbecue",
+            "fi": "grilli",
+            "nl": "de barbecue"
         },
         "plural": {
-            "en": "Barbecues",
-            "fi": "Grillit",
-            "nl": "De barbecues"
+            "en": "barbecues",
+            "fi": "grillit",
+            "nl": "de barbecues"
         }
     },
     "wall": {
@@ -148,14 +148,14 @@
             ]
         },
         "singular": {
-            "en": "Wall",
-            "fi": "Seinä",
-            "nl": "De muur"
+            "en": "wall",
+            "fi": "seinä",
+            "nl": "de muur"
         },
         "plural": {
-            "en": "Walls",
-            "fi": "Seinät",
-            "nl": "De muren"
+            "en": "walls",
+            "fi": "seinät",
+            "nl": "de muren"
         }
     },
     "floor": {
@@ -166,14 +166,14 @@
             ]
         },
         "singular": {
-            "en": "Floor",
-            "fi": "Lattia",
-            "nl": "De vloer"
+            "en": "floor",
+            "fi": "lattia",
+            "nl": "de vloer"
         },
         "plural": {
-            "en": "Floors",
-            "fi": "Lattiat",
-            "nl": "De vloeren"
+            "en": "floors",
+            "fi": "lattiat",
+            "nl": "de vloeren"
         }
     },
     "door": {
@@ -185,14 +185,14 @@
             ]
         },
         "singular": {
-            "en": "Door",
-            "fi": "Ovi",
-            "nl": "De deur"
+            "en": "door",
+            "fi": "ovi",
+            "nl": "de deur"
         },
         "plural": {
-            "en": "Doors",
-            "fi": "Ovet",
-            "nl": "De deuren"
+            "en": "doors",
+            "fi": "ovet",
+            "nl": "de deuren"
         }
     },
     "window": {
@@ -204,14 +204,14 @@
             ]
         },
         "singular": {
-            "en": "Window",
-            "fi": "Ikkuna",
-            "nl": "Het raam"
+            "en": "window",
+            "fi": "ikkuna",
+            "nl": "het raam"
         },
         "plural": {
-            "en": "Windows",
-            "fi": "Ikkunat",
-            "nl": "De ramen"
+            "en": "windows",
+            "fi": "ikkunat",
+            "nl": "de ramen"
         }
     },
     "stairs": {
@@ -222,15 +222,15 @@
             ]
         },
         "singular": {
-            "en": "Stairs",
+            "en": "stairs",
             "fi": [
-                "Portaat",
-                "Rappuset"
+                "portaat",
+                "rappuset"
             ],
-            "nl": "De trap"
+            "nl": "de trap"
         },
         "plural": {
-            "nl": "De trappen"
+            "nl": "de trappen"
         }
     },
     "living room": {
@@ -253,19 +253,19 @@
             ]
         },
         "singular": {
-            "en": "Living room",
-            "fi": "Olohuone",
+            "en": "living room",
+            "fi": "olohuone",
             "nl": [
-                "De huiskamer",
-                "De woonkamer"
+                "de huiskamer",
+                "de woonkamer"
             ]
         },
         "plural": {
             "en": "living rooms",
-            "fi": "Olohuoneet",
+            "fi": "olohuoneet",
             "nl": [
-                "De huiskamers",
-                "De woonkamers"
+                "de huiskamers",
+                "de woonkamers"
             ]
         }
     },
@@ -277,14 +277,14 @@
             ]
         },
         "singular": {
-            "en": "Kitchen",
-            "fi": "Keittiö",
-            "nl": "De keuken"
+            "en": "kitchen",
+            "fi": "keittiö",
+            "nl": "de keuken"
         },
         "plural": {
-            "en": "Kitchens",
-            "fi": "Keittiöt",
-            "nl": "De keukens"
+            "en": "kitchens",
+            "fi": "keittiöt",
+            "nl": "de keukens"
         }
     },
     "bedroom": {
@@ -306,14 +306,14 @@
             ]
         },
         "singular": {
-            "en": "Bedroom",
-            "fi": "Makuuhuone",
-            "nl": "De slaapkamer"
+            "en": "bedroom",
+            "fi": "makuuhuone",
+            "nl": "de slaapkamer"
         },
         "plural": {
-            "en": "Bedrooms",
-            "fi": "Makuuhuoneet",
-            "nl": "De slaapkamers"
+            "en": "bedrooms",
+            "fi": "makuuhuoneet",
+            "nl": "de slaapkamers"
         }
     },
     "bathroom": {
@@ -325,14 +325,14 @@
         },
         "roots": "room",
         "singular": {
-            "en": "Bathroom",
-            "fi": "Kylpyhuone",
-            "nl": "De badkamer"
+            "en": "bathroom",
+            "fi": "kylpyhuone",
+            "nl": "de badkamer"
         },
         "plural": {
-            "en": "Bathrooms",
-            "fi": "Kylpyhuoneet",
-            "nl": "De badkamers"
+            "en": "bathrooms",
+            "fi": "kylpyhuoneet",
+            "nl": "de badkamers"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/languages.json b/src/topics/languages.json
index 713b1bf5..03fc51b4 100644
--- a/src/topics/languages.json
+++ b/src/topics/languages.json
@@ -8,14 +8,14 @@
             ]
         },
         "singular": {
-            "en": "Language",
-            "fi": "Kieli",
-            "nl": "De taal"
+            "en": "language",
+            "fi": "kieli",
+            "nl": "de taal"
         },
         "plural": {
-            "en": "Languages",
-            "fi": "Kielet",
-            "nl": "De talen"
+            "en": "languages",
+            "fi": "kielet",
+            "nl": "de talen"
         }
     },
     "dialect": {
@@ -24,14 +24,14 @@
             "C2": "EP"
         },
         "singular": {
-            "en": "Dialect",
-            "fi": "Murre",
-            "nl": "Het dialect"
+            "en": "dialect",
+            "fi": "murre",
+            "nl": "het dialect"
         },
         "plural": {
-            "en": "Dialects",
-            "fi": "Murteet",
-            "nl": "De dialecten"
+            "en": "dialects",
+            "fi": "murteet",
+            "nl": "de dialecten"
         }
     },
     "accent": {
@@ -40,14 +40,14 @@
             "C2": "EP"
         },
         "singular": {
-            "en": "Accent",
-            "fi": "Aksentti",
-            "nl": "Het accent"
+            "en": "accent",
+            "fi": "aksentti",
+            "nl": "het accent"
         },
         "plural": {
-            "en": "Accents",
-            "fi": "Aksentit",
-            "nl": "De accenten"
+            "en": "accents",
+            "fi": "aksentit",
+            "nl": "de accenten"
         }
     },
     "english": {
@@ -56,7 +56,7 @@
             "C1": "EP"
         },
         "en": "English",
-        "fi": "Englanti;language",
+        "fi": "englanti",
         "nl": "Engels"
     },
     "chinese": {
@@ -67,7 +67,7 @@
             ]
         },
         "en": "Chinese",
-        "fi": "Kiina;language",
+        "fi": "kiina",
         "nl": "Chinees"
     },
     "german": {
@@ -78,7 +78,7 @@
             ]
         },
         "en": "German",
-        "fi": "Saksa;language",
+        "fi": "saksa",
         "nl": "Duits"
     },
     "estonian": {
@@ -89,7 +89,7 @@
             ]
         },
         "en": "Estonian",
-        "fi": "Viro;language",
+        "fi": "viro",
         "nl": "Estisch"
     },
     "finnish": {
@@ -101,7 +101,7 @@
             ]
         },
         "en": "Finnish",
-        "fi": "Suomi;language",
+        "fi": "suomi",
         "nl": "Fins"
     },
     "french": {
@@ -112,7 +112,7 @@
             ]
         },
         "en": "French",
-        "fi": "Ranska;language",
+        "fi": "ranska",
         "nl": "Frans"
     },
     "hungarian": {
@@ -123,7 +123,7 @@
             ]
         },
         "en": "Hungarian",
-        "fi": "Unkari;language",
+        "fi": "unkari",
         "nl": "Hongaars"
     },
     "japanese": {
@@ -134,7 +134,7 @@
             ]
         },
         "en": "Japanese",
-        "fi": "Japani;language",
+        "fi": "japani",
         "nl": "Japans"
     },
     "korean": {
@@ -145,7 +145,7 @@
             ]
         },
         "en": "Korean",
-        "fi": "Korea;language",
+        "fi": "korea",
         "nl": "Koreaans"
     },
     "spanish": {
@@ -154,7 +154,7 @@
             "none": "OD"
         },
         "en": "Spanish",
-        "fi": "Espanja;language",
+        "fi": "espanja",
         "nl": "Spaans"
     },
     "dutch": {
@@ -165,7 +165,7 @@
             ]
         },
         "en": "Dutch",
-        "fi": "Hollanti",
+        "fi": "hollanti",
         "nl": "Nederlands"
     },
     "danish": {
@@ -176,7 +176,7 @@
             ]
         },
         "en": "Danish",
-        "fi": "Tanska;language",
+        "fi": "tanska",
         "nl": "Deens"
     },
     "norwegian": {
@@ -187,7 +187,7 @@
             ]
         },
         "en": "Norwegian",
-        "fi": "Norja;language",
+        "fi": "norja",
         "nl": "Noors"
     },
     "swedish": {
@@ -198,7 +198,7 @@
             ]
         },
         "en": "Swedish",
-        "fi": "Ruotsi;language",
+        "fi": "ruotsi",
         "nl": "Zweeds"
     },
     "russian": {
@@ -209,7 +209,7 @@
             ]
         },
         "en": "Russian",
-        "fi": "Venäjä;language",
+        "fi": "venäjä",
         "nl": "Russisch"
     },
     "icelandic": {
@@ -220,7 +220,7 @@
             ]
         },
         "en": "Icelandic",
-        "fi": "Islanti;language",
+        "fi": "islanti",
         "nl": "IJslands"
     },
     "I have a dutch accent": {
diff --git a/src/topics/months.json b/src/topics/months.json
index 861d4d96..441ff81e 100644
--- a/src/topics/months.json
+++ b/src/topics/months.json
@@ -11,14 +11,14 @@
             "nl": "moon"
         },
         "singular": {
-            "en": "Month",
-            "fi": "Kuukausi",
-            "nl": "De maand"
+            "en": "month",
+            "fi": "kuukausi",
+            "nl": "de maand"
         },
         "plural": {
-            "en": "Months",
-            "fi": "Kuukaudet",
-            "nl": "De maanden"
+            "en": "months",
+            "fi": "kuukaudet",
+            "nl": "de maanden"
         }
     },
     "moon": {
@@ -29,14 +29,14 @@
             ]
         },
         "singular": {
-            "en": "Moon",
-            "fi": "Kuu",
-            "nl": "De maan"
+            "en": "moon",
+            "fi": "kuu",
+            "nl": "de maan"
         },
         "plural": {
-            "en": "Moons",
-            "fi": "Kuut",
-            "nl": "De manen"
+            "en": "moons",
+            "fi": "kuut",
+            "nl": "de manen"
         }
     },
     "january": {
diff --git a/src/topics/nature.json b/src/topics/nature.json
index 2f197217..cfd8a1f2 100644
--- a/src/topics/nature.json
+++ b/src/topics/nature.json
@@ -7,9 +7,9 @@
                 "OD"
             ]
         },
-        "en": "Nature",
-        "fi": "Luonto",
-        "nl": "De natuur"
+        "en": "nature",
+        "fi": "luonto",
+        "nl": "de natuur"
     },
     "forest": {
         "level": {
@@ -21,24 +21,24 @@
         },
         "singular": {
             "en": [
-                "Forest",
-                "Wood"
+                "forest",
+                "wood"
             ],
-            "fi": "Metsä",
+            "fi": "metsä",
             "nl": [
-                "Het bos",
-                "Het woud"
+                "het bos",
+                "het woud"
             ]
         },
         "plural": {
             "en": [
-                "Forests",
-                "Woods"
+                "forests",
+                "woods"
             ],
-            "fi": "Metsät",
+            "fi": "metsät",
             "nl": [
-                "De bossen",
-                "De wouden"
+                "de bossen",
+                "de wouden"
             ]
         }
     },
@@ -50,14 +50,14 @@
             ]
         },
         "singular": {
-            "en": "Flower",
-            "fi": "Kukka",
-            "nl": "De bloem"
+            "en": "flower",
+            "fi": "kukka",
+            "nl": "de bloem"
         },
         "plural": {
-            "en": "Flowers",
-            "fi": "Kukat",
-            "nl": "De bloemen"
+            "en": "flowers",
+            "fi": "kukat",
+            "nl": "de bloemen"
         }
     },
     "lake": {
@@ -68,14 +68,14 @@
             ]
         },
         "singular": {
-            "en": "Lake",
-            "fi": "Järvi",
-            "nl": "Het meer"
+            "en": "lake",
+            "fi": "järvi",
+            "nl": "het meer"
         },
         "plural": {
-            "en": "Lakes",
-            "fi": "Järvet",
-            "nl": "De meren"
+            "en": "lakes",
+            "fi": "järvet",
+            "nl": "de meren"
         }
     },
     "sea": {
@@ -87,14 +87,14 @@
             ]
         },
         "singular": {
-            "en": "Sea",
-            "fi": "Meri",
-            "nl": "De zee"
+            "en": "sea",
+            "fi": "meri",
+            "nl": "de zee"
         },
         "plural": {
-            "en": "Seas",
-            "fi": "Meret",
-            "nl": "De zeeën"
+            "en": "seas",
+            "fi": "meret",
+            "nl": "de zeeën"
         }
     },
     "river": {
@@ -105,14 +105,14 @@
             ]
         },
         "singular": {
-            "en": "River",
-            "fi": "Joki",
-            "nl": "De rivier"
+            "en": "river",
+            "fi": "joki",
+            "nl": "de rivier"
         },
         "plural": {
-            "en": "Rivers",
-            "fi": "Joet",
-            "nl": "De rivieren"
+            "en": "rivers",
+            "fi": "joet",
+            "nl": "de rivieren"
         }
     },
     "island": {
@@ -121,14 +121,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Island",
-            "fi": "Saari",
-            "nl": "Het eiland"
+            "en": "island",
+            "fi": "saari",
+            "nl": "het eiland"
         },
         "plural": {
-            "en": "Islands",
-            "fi": "Saaret",
-            "nl": "De eilanden"
+            "en": "islands",
+            "fi": "saaret",
+            "nl": "de eilanden"
         }
     },
     "coast": {
@@ -140,14 +140,14 @@
             "fi": "beach"
         },
         "singular": {
-            "en": "Coast",
-            "fi": "Rannikko",
-            "nl": "De kust"
+            "en": "coast",
+            "fi": "rannikko",
+            "nl": "de kust"
         },
         "plural": {
-            "en": "Coasts",
-            "fi": "Rannikot",
-            "nl": "De kusten"
+            "en": "coasts",
+            "fi": "rannikot",
+            "nl": "de kusten"
         }
     },
     "desert": {
@@ -161,20 +161,20 @@
             "fi": "country"
         },
         "singular": {
-            "en": "Desert",
+            "en": "desert",
             "fi": [
-                "Aavikko",
-                "Autiomaa"
+                "aavikko",
+                "autiomaa"
             ],
-            "nl": "De woestijn"
+            "nl": "de woestijn"
         },
         "plural": {
-            "en": "Deserts",
+            "en": "deserts",
             "fi": [
-                "Aavikot",
-                "Autiomaat"
+                "aavikot",
+                "autiomaat"
             ],
-            "nl": "De woestijnen"
+            "nl": "de woestijnen"
         }
     },
     "tree": {
@@ -186,14 +186,14 @@
             ]
         },
         "singular": {
-            "en": "Tree",
-            "fi": "Puu",
-            "nl": "De boom"
+            "en": "tree",
+            "fi": "puu",
+            "nl": "de boom"
         },
         "plural": {
-            "en": "Trees",
-            "fi": "Puut",
-            "nl": "De bomen"
+            "en": "trees",
+            "fi": "puut",
+            "nl": "de bomen"
         }
     },
     "beach": {
@@ -205,14 +205,14 @@
             ]
         },
         "singular": {
-            "en": "Beach",
-            "fi": "Ranta",
-            "nl": "Het strand"
+            "en": "beach",
+            "fi": "ranta",
+            "nl": "het strand"
         },
         "plural": {
-            "en": "Beaches",
-            "fi": "Rannat",
-            "nl": "De stranden"
+            "en": "beaches",
+            "fi": "rannat",
+            "nl": "de stranden"
         }
     },
     "valley": {
@@ -221,14 +221,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Valley",
-            "fi": "Laakso",
-            "nl": "De vallei"
+            "en": "valley",
+            "fi": "laakso",
+            "nl": "de vallei"
         },
         "plural": {
-            "en": "Valleys",
-            "fi": "Laaksot",
-            "nl": "De valleien"
+            "en": "valleys",
+            "fi": "laaksot",
+            "nl": "de valleien"
         }
     },
     "hill": {
@@ -239,20 +239,20 @@
             ]
         },
         "singular": {
-            "en": "Hill",
+            "en": "hill",
             "fi": [
-                "Mäki",
-                "Kukkula"
+                "mäki",
+                "kukkula"
             ],
-            "nl": "De heuvel"
+            "nl": "de heuvel"
         },
         "plural": {
-            "en": "Hills",
+            "en": "hills",
             "fi": [
-                "Mäet",
-                "Kukkulat"
+                "mäet",
+                "kukkulat"
             ],
-            "nl": "De heuvels"
+            "nl": "de heuvels"
         }
     },
     "mountain": {
@@ -261,14 +261,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Mountain",
-            "fi": "Vuori",
-            "nl": "De berg"
+            "en": "mountain",
+            "fi": "vuori",
+            "nl": "de berg"
         },
         "plural": {
-            "en": "Mountains",
-            "fi": "Vuoret",
-            "nl": "De bergen"
+            "en": "mountains",
+            "fi": "vuoret",
+            "nl": "de bergen"
         }
     },
     "north": {
@@ -276,36 +276,36 @@
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "North|The north",
-        "fi": "Pohjoinen",
-        "nl": "Het noorden"
+        "en": "north|the North",
+        "fi": "pohjoinen",
+        "nl": "het noorden"
     },
     "east": {
         "level": {
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "East|The east",
-        "fi": "Itä",
-        "nl": "Het oosten"
+        "en": "east|the East",
+        "fi": "itä",
+        "nl": "het oosten"
     },
     "south": {
         "level": {
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "South|The south",
-        "fi": "Etelä",
-        "nl": "Het zuiden"
+        "en": "south|the South",
+        "fi": "etelä",
+        "nl": "het zuiden"
     },
     "west": {
         "level": {
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "West|The west",
-        "fi": "Länsi",
-        "nl": "Het westen"
+        "en": "west|the West",
+        "fi": "länsi",
+        "nl": "het westen"
     },
     "world": {
         "level": {
@@ -318,9 +318,9 @@
         "roots": {
             "fi": "country"
         },
-        "en": "World",
-        "fi": "Maailma",
-        "nl": "De wereld"
+        "en": "world",
+        "fi": "maailma",
+        "nl": "de wereld"
     },
     "continent": {
         "level": {
@@ -331,14 +331,14 @@
             "fi": "country"
         },
         "singular": {
-            "en": "Continent",
-            "fi": "Maanosa",
-            "nl": "Het continent"
+            "en": "continent",
+            "fi": "maanosa",
+            "nl": "het continent"
         },
         "plural": {
-            "en": "Continents",
-            "fi": "Maanosat",
-            "nl": "De continenten"
+            "en": "continents",
+            "fi": "maanosat",
+            "nl": "de continenten"
         }
     },
     "sand": {
@@ -349,14 +349,14 @@
             ]
         },
         "singular": {
-            "en": "Sand",
-            "fi": "Hiekka",
-            "nl": "Het zand"
+            "en": "sand",
+            "fi": "hiekka",
+            "nl": "het zand"
         },
         "plural": {
-            "en": "Sands",
-            "fi": "Hiekat",
-            "nl": "De zanden"
+            "en": "sands",
+            "fi": "hiekat",
+            "nl": "de zanden"
         }
     },
     "ground": {
@@ -365,14 +365,14 @@
             "B1": "B1"
         },
         "singular": {
-            "en": "Ground",
-            "fi": "Maa;solid surface of the earth",
-            "nl": "De grond"
+            "en": "ground",
+            "fi": "maa;solid surface of the earth",
+            "nl": "de grond"
         },
         "plural": {
-            "en": "Grounds",
-            "fi": "Maat;solid surfaces of the earth",
-            "nl": "De gronden"
+            "en": "grounds",
+            "fi": "maat;solid surfaces of the earth",
+            "nl": "de gronden"
         }
     },
     "stone": {
@@ -381,14 +381,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Stone",
-            "fi": "Kivi",
-            "nl": "De steen"
+            "en": "stone",
+            "fi": "kivi",
+            "nl": "de steen"
         },
         "plural": {
-            "en": "Stones",
-            "fi": "Kivet",
-            "nl": "De stenen"
+            "en": "stones",
+            "fi": "kivet",
+            "nl": "de stenen"
         }
     },
     "fire": {
@@ -397,14 +397,14 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Fire",
-            "fi": "Tuli",
-            "nl": "Het vuur"
+            "en": "fire",
+            "fi": "tuli",
+            "nl": "het vuur"
         },
         "plural": {
-            "en": "Fires",
-            "fi": "Tulet",
-            "nl": "De vuren"
+            "en": "fires",
+            "fi": "tulet",
+            "nl": "de vuren"
         }
     },
     "volcano": {
@@ -419,14 +419,14 @@
             ]
         },
         "singular": {
-            "en": "Volcano",
-            "fi": "Tulivuori",
-            "nl": "De vulkaan"
+            "en": "volcano",
+            "fi": "tulivuori",
+            "nl": "de vulkaan"
         },
         "plural": {
-            "en": "Volcanoes|Volcanos",
-            "fi": "Tulivuoret",
-            "nl": "De vulkanen"
+            "en": "volcanoes|Volcanos",
+            "fi": "tulivuoret",
+            "nl": "de vulkanen"
         }
     },
     "cave": {
@@ -435,14 +435,14 @@
             "B2": "OD"
         },
         "singular": {
-            "en": "Cave",
-            "fi": "Luola",
-            "nl": "De grot"
+            "en": "cave",
+            "fi": "luola",
+            "nl": "de grot"
         },
         "plural": {
-            "en": "Caves",
-            "fi": "Luolat",
-            "nl": "De grotten"
+            "en": "caves",
+            "fi": "luolat",
+            "nl": "de grotten"
         }
     },
     "canyon": {
@@ -451,14 +451,14 @@
             "none": "EP"
         },
         "singular": {
-            "en": "Canyon",
-            "fi": "Rotko",
-            "nl": "De kloof"
+            "en": "canyon",
+            "fi": "rotko",
+            "nl": "de kloof"
         },
         "plural": {
-            "en": "Canyons",
-            "fi": "Rotkot",
-            "nl": "De kloven"
+            "en": "canyons",
+            "fi": "rotkot",
+            "nl": "de kloven"
         }
     },
     "rainforest": {
@@ -471,14 +471,14 @@
             "forest"
         ],
         "singular": {
-            "en": "Rainforest|Rain forest",
-            "fi": "Sademetsä",
-            "nl": "Het regenwoud"
+            "en": "Rainforest|rain forest",
+            "fi": "sademetsä",
+            "nl": "het regenwoud"
         },
         "plural": {
-            "en": "Rainforests|Rain forests",
-            "fi": "Sademetsät",
-            "nl": "De regenwouden"
+            "en": "rainforests|rain forests",
+            "fi": "sademetsät",
+            "nl": "de regenwouden"
         }
     },
     "glacier": {
@@ -490,16 +490,36 @@
             "fi": "ice"
         },
         "singular": {
-            "en": "Glacier",
-            "fi": "Jäätikkö",
-            "nl": "De gletsjer"
-        },
-        "plural":  {
-            "en": "Glaciers",
-            "fi": "Jäätiköt",
-            "nl": "De gletsjers"
+            "en": "glacier",
+            "fi": "jäätikkö",
+            "nl": "de gletsjer"
+        },
+        "plural": {
+            "en": "glaciers",
+            "fi": "jäätiköt",
+            "nl": "de gletsjers"
         }
     },
+    "northern lights": {
+        "level": {
+            "C2": "OD",
+            "none": "EP"
+        },
+        "roots": {
+            "en": [
+                "north",
+                "light"
+            ],
+            "fi": "fire",
+            "nl": [
+                "north",
+                "light"
+            ]
+        },
+        "en": "northern lights",
+        "fi": "revontulet",
+        "nl": "noorderlicht"
+    },
     "it is cold in the north": {
         "roots": [
             "to be",
diff --git a/src/topics/objects.json b/src/topics/objects.json
index 9a737032..e943baf7 100644
--- a/src/topics/objects.json
+++ b/src/topics/objects.json
@@ -8,14 +8,14 @@
             ]
         },
         "singular": {
-            "en": "Book",
-            "fi": "Kirja",
-            "nl": "Het boek"
+            "en": "book",
+            "fi": "kirja",
+            "nl": "het boek"
         },
         "plural": {
-            "en": "Books",
-            "fi": "Kirjat",
-            "nl": "De boeken"
+            "en": "books",
+            "fi": "kirjat",
+            "nl": "de boeken"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/possessive_adjectives.json b/src/topics/possessive_adjectives.json
index b550ae90..0c669eb4 100644
--- a/src/topics/possessive_adjectives.json
+++ b/src/topics/possessive_adjectives.json
@@ -2,185 +2,185 @@
     "my cat": {
         "roots": "cat",
         "singular": {
-            "en": "My cat",
-            "fi": "Minun kissani;singular",
-            "nl": "Mijn kat"
+            "en": "my cat",
+            "fi": "minun kissani;singular",
+            "nl": "mijn kat"
         },
         "plural": {
-            "en": "My cats",
-            "fi": "Minun kissani;plural",
-            "nl": "Mijn katten"
+            "en": "my cats",
+            "fi": "minun kissani;plural",
+            "nl": "mijn katten"
         }
     },
     "your cat": {
         "roots": "cat",
         "singular": {
-            "en": "Your cat;singular",
-            "fi": "Sinun kissasi;singular",
-            "nl": "Jouw kat"
+            "en": "your cat;singular",
+            "fi": "sinun kissasi;singular",
+            "nl": "jouw kat"
         },
         "plural": {
-            "en": "Your cats;singular",
-            "fi": "Sinun kissasi;plural",
-            "nl": "Jouw katten"
+            "en": "your cats;singular",
+            "fi": "sinun kissasi;plural",
+            "nl": "jouw katten"
         }
     },
-    "hes or his cat": {
+    "her or his cat": {
         "roots": "cat",
         "female": {
             "singular": {
-                "en": "Her cat",
-                "fi": "Hänen kissansa;female singular",
-                "nl": "Haar kat"
+                "en": "her cat",
+                "fi": "hänen kissansa;female singular",
+                "nl": "haar kat"
             },
             "plural": {
-                "en": "Her cats",
-                "fi": "Hänen kissansa;female plural",
-                "nl": "Haar katten"
+                "en": "her cats",
+                "fi": "hänen kissansa;female plural",
+                "nl": "haar katten"
             }
         },
         "male": {
             "singular": {
-                "en": "His cat",
-                "fi": "Hänen kissansa;male singular",
-                "nl": "Zijn kat"
+                "en": "his cat",
+                "fi": "hänen kissansa;male singular",
+                "nl": "zijn kat"
             },
             "plural": {
-                "en": "His cats",
-                "fi": "Hänen kissansa;male plural",
-                "nl": "Zijn katten"
+                "en": "his cats",
+                "fi": "hänen kissansa;male plural",
+                "nl": "zijn katten"
             }
         }
     },
     "our cat": {
         "roots": "cat",
         "singular": {
-            "en": "Our cat",
-            "fi": "Meidän kissamme;singular",
-            "nl": "Onze kat"
+            "en": "our cat",
+            "fi": "meidän kissamme;singular",
+            "nl": "onze kat"
         },
         "plural": {
-            "en": "Our cats",
-            "fi": "Meidän kissamme;plural",
-            "nl": "Onze katten"
+            "en": "our cats",
+            "fi": "meidän kissamme;plural",
+            "nl": "onze katten"
         }
     },
     "your (pl) cat": {
         "roots": "cat",
         "singular": {
-            "en": "Yuur cat;plural",
-            "fi": "Teidän kissanne;singular",
-            "nl": "Jullie kat"
+            "en": "your cat;plural",
+            "fi": "teidän kissanne;singular",
+            "nl": "jullie kat"
         },
         "plural": {
-            "en": "Your cats;plural",
-            "fi": "Teidän kissanne;plural",
-            "nl": "Jullie katten"
+            "en": "your cats;plural",
+            "fi": "teidän kissanne;plural",
+            "nl": "jullie katten"
         }
     },
     "their cat": {
         "roots": "cat",
         "singular": {
-            "en": "Their cat",
-            "fi": "Heidän kissansa;singular",
-            "nl": "Hun kat"
+            "en": "their cat",
+            "fi": "heidän kissansa;singular",
+            "nl": "hun kat"
         },
         "plural": {
-            "en": "Their cats",
-            "fi": "Heidän kissansa;plural",
-            "nl": "Hun katten"
+            "en": "their cats",
+            "fi": "heidän kissansa;plural",
+            "nl": "hun katten"
         }
     },
     "my house": {
         "roots": "house",
         "singular": {
-            "en": "My house",
-            "fi": "Minun taloni;singular",
-            "nl": "Mijn huis"
+            "en": "my house",
+            "fi": "minun taloni;singular",
+            "nl": "mijn huis"
         },
         "plural": {
-            "en": "My houses",
-            "fi": "Minun taloni;plural",
-            "nl": "Mijn huizen"
+            "en": "my houses",
+            "fi": "minun taloni;plural",
+            "nl": "mijn huizen"
         }
     },
     "your house": {
         "roots": "house",
         "singular": {
-            "en": "Your house;singular",
-            "fi": "Sinun talosi;singular",
-            "nl": "Jouw huis"
+            "en": "your house;singular",
+            "fi": "sinun talosi;singular",
+            "nl": "jouw huis"
         },
         "plural": {
-            "en": "Your houses;singular",
-            "fi": "Sinun talosi;plural",
-            "nl": "Jouw huizen"
+            "en": "your houses;singular",
+            "fi": "sinun talosi;plural",
+            "nl": "jouw huizen"
         }
     },
     "her or his house": {
         "roots": "house",
         "female": {
             "singular": {
-                "en": "Her house",
-                "fi": "Hänen talonsa;female singular",
-                "nl": "Haar huis"
+                "en": "her house",
+                "fi": "hänen talonsa;female singular",
+                "nl": "haar huis"
             },
             "plural": {
-                "en": "Her houses",
-                "fi": "Hänen talonsa;female plural",
-                "nl": "Haar huizen"
+                "en": "her houses",
+                "fi": "hänen talonsa;female plural",
+                "nl": "haar huizen"
             }
         },
         "male": {
             "singular": {
-                "en": "His house",
-                "fi": "Hänen talonsa;male singular",
-                "nl": "Zijn huis"
+                "en": "his house",
+                "fi": "hänen talonsa;male singular",
+                "nl": "zijn huis"
             },
             "plural": {
-                "en": "His houses",
-                "fi": "Hänen talonsa;male plural",
-                "nl": "Zijn huizen"
+                "en": "his houses",
+                "fi": "hänen talonsa;male plural",
+                "nl": "zijn huizen"
             }
         }
     },
     "our house": {
         "roots": "house",
         "singular": {
-            "en": "Our house",
-            "fi": "Meidän talomme;singular",
-            "nl": "Ons huis"
+            "en": "our house",
+            "fi": "meidän talomme;singular",
+            "nl": "ons huis"
         },
         "plural": {
-            "en": "Our houses",
-            "fi": "Meidän talomme;plural",
-            "nl": "Onze huizen"
+            "en": "our houses",
+            "fi": "meidän talomme;plural",
+            "nl": "onze huizen"
         }
     },
     "your (pl) house": {
         "roots": "house",
         "singular": {
-            "en": "Your house;plural",
-            "fi": "Teidän talonne;singular",
-            "nl": "Jullie huis"
+            "en": "your house;plural",
+            "fi": "teidän talonne;singular",
+            "nl": "jullie huis"
         },
         "plural": {
-            "en": "Your houses;plural",
-            "fi": "Teidän talonne;plural",
-            "nl": "Jullie huizen"
+            "en": "your houses;plural",
+            "fi": "teidän talonne;plural",
+            "nl": "jullie huizen"
         }
     },
     "their house": {
         "roots": "house",
         "singular": {
-            "en": "Their house",
-            "fi": "Heidän talonsa;singular",
-            "nl": "Hun huis"
+            "en": "their house",
+            "fi": "heidän talonsa;singular",
+            "nl": "hun huis"
         },
         "plural": {
-            "en": "Their houses",
-            "fi": "Heidän talonsa;plural",
-            "nl": "Hun huizen"
+            "en": "their houses",
+            "fi": "heidän talonsa;plural",
+            "nl": "hun huizen"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/seasons.json b/src/topics/seasons.json
index a370c82a..42436f8b 100644
--- a/src/topics/seasons.json
+++ b/src/topics/seasons.json
@@ -5,14 +5,14 @@
             "B1": "EP"
         },
         "singular": {
-            "en": "Season",
-            "fi": "Vuodenaika",
-            "nl": "Het seizoen"
+            "en": "season",
+            "fi": "vuodenaika",
+            "nl": "het seizoen"
         },
         "plural": {
-            "en": "Seasons",
-            "fi": "Vuodenajat",
-            "nl": "De seizoenen"
+            "en": "seasons",
+            "fi": "vuodenajat",
+            "nl": "de seizoenen"
         }
     },
     "spring": {
@@ -24,47 +24,47 @@
             "A2": "EP"
         },
         "singular": {
-            "en": "Spring",
-            "fi": "Kevät",
+            "en": "spring",
+            "fi": "kevät",
             "nl": [
-                "De lente",
-                "Het voorjaar"
+                "de lente",
+                "het voorjaar"
             ]
         },
         "plural": {
-            "en": "Springs",
-            "fi": "Keväät",
+            "en": "springs",
+            "fi": "keväät",
             "nl": [
-                "De lentes",
-                "De voorjaren"
+                "de lentes",
+                "de voorjaren"
             ]
         }
     },
     "in spring": {
         "roots": "spring",
-        "en": "In spring",
-        "fi": "Keväällä",
+        "en": "in spring",
+        "fi": "keväällä",
         "nl": [
-            "In de lente",
-            "In het voorjaar"
+            "in de lente",
+            "in het voorjaar"
         ]
     },
     "next spring": {
         "roots": "spring",
-        "en": "Next spring",
-        "fi": "Ensi keväänä",
+        "en": "next spring",
+        "fi": "ensi keväänä",
         "nl": [
-            "Volgende lente",
-            "Volgend voorjaar"
+            "volgende lente",
+            "volgend voorjaar"
         ]
     },
     "last spring": {
         "roots": "spring",
-        "en": "Last spring",
-        "fi": "Viime keväänä",
+        "en": "last spring",
+        "fi": "viime keväänä",
         "nl": [
-            "Vorige lente",
-            "Vorig voorjaar"
+            "vorige lente",
+            "vorig voorjaar"
         ]
     },
     "summer": {
@@ -76,33 +76,33 @@
             ]
         },
         "singular": {
-            "en": "Summer",
-            "fi": "Kesä",
-            "nl": "De zomer"
+            "en": "summer",
+            "fi": "kesä",
+            "nl": "de zomer"
         },
         "plural": {
-            "en": "Summers",
-            "fi": "Kesät",
-            "nl": "De zomers"
+            "en": "summers",
+            "fi": "kesät",
+            "nl": "de zomers"
         }
     },
     "in summer": {
         "roots": "summer",
-        "en": "In summer",
-        "fi": "Kesällä",
-        "nl": "In de zomer"
+        "en": "in summer",
+        "fi": "kesällä",
+        "nl": "in de zomer"
     },
     "next summer": {
         "roots": "summer",
-        "en": "Next summer",
-        "fi": "Ensi kesänä",
-        "nl": "Volgende zomer"
+        "en": "next summer",
+        "fi": "ensi kesänä",
+        "nl": "volgende zomer"
     },
     "last summer": {
         "roots": "summer",
-        "en": "Last summer",
-        "fi": "Viime kesänä",
-        "nl": "Vorige zomer"
+        "en": "last summer",
+        "fi": "viime kesänä",
+        "nl": "vorige zomer"
     },
     "autumn": {
         "level": {
@@ -114,55 +114,61 @@
         },
         "singular": {
             "en": [
-                "Autumn",
-                "Fall"
+                "autumn",
+                "fall"
             ],
-            "fi": "Syksy",
+            "fi": "syksy",
             "nl": [
-                "De herfst",
-                "Het najaar"
+                "de herfst",
+                "het najaar"
             ]
         },
         "plural": {
             "en": [
-                "Autumns",
-                "Falls"
+                "autumns",
+                "falls"
             ],
-            "fi": "Syksyt",
+            "fi": "syksyt",
             "nl": [
-                "De herfsten",
-                "De najaren"
+                "de herfsten",
+                "de najaren"
             ]
         }
     },
     "in autumn": {
         "roots": "autumn",
         "en": [
-            "In autumn",
-            "In fall"
+            "in autumn",
+            "in fall"
         ],
-        "fi": "Syksyllä",
+        "fi": "syksyllä",
         "nl": [
-            "In de herfst",
-            "In het najaar"
+            "in de herfst",
+            "in het najaar"
         ]
     },
     "next autumn": {
         "roots": "autumn",
-        "en": "Next autumn|Next fall",
-        "fi": "Ensi syksynä",
+        "en": [
+            "next autumn",
+            "next fall"
+        ],
+        "fi": "ensi syksynä",
         "nl": [
-            "Volgende herfst",
-            "Volgend najaar"
+            "volgende herfst",
+            "volgend najaar"
         ]
     },
     "last autumn": {
         "roots": "autumn",
-        "en": "Last autumn",
-        "fi": "Viime syksynä",
+        "en": [
+            "last autumn",
+            "last fall"
+        ],
+        "fi": "viime syksynä",
         "nl": [
-            "Vorige herfst",
-            "Vorig najaar"
+            "vorige herfst",
+            "vorig najaar"
         ]
     },
     "winter": {
@@ -174,33 +180,33 @@
             ]
         },
         "singular": {
-            "en": "Winter",
-            "fi": "Talvi",
-            "nl": "De winter"
+            "en": "winter",
+            "fi": "talvi",
+            "nl": "de winter"
         },
         "plural": {
-            "en": "Winters",
-            "fi": "Talvet",
-            "nl": "De winters"
+            "en": "winters",
+            "fi": "talvet",
+            "nl": "de winters"
         }
     },
     "in winter": {
         "roots": "winter",
-        "en": "In winter",
-        "fi": "Talvella",
-        "nl": "In de winter"
+        "en": "in winter",
+        "fi": "talvella",
+        "nl": "in de winter"
     },
     "next winter": {
         "roots": "winter",
-        "en": "Next winter",
-        "fi": "Ensi talvena",
-        "nl": "Volgende winter"
+        "en": "next winter",
+        "fi": "ensi talvena",
+        "nl": "volgende winter"
     },
     "last winter": {
         "roots": "winter",
-        "en": "Last winter",
-        "fi": "Viime talvena",
-        "nl": "Vorige winter"
+        "en": "last winter",
+        "fi": "viime talvena",
+        "nl": "vorige winter"
     },
     "the finnish winter is cold": {
         "roots": [
diff --git a/src/topics/time.json b/src/topics/time.json
index bf14a6e5..451c224a 100644
--- a/src/topics/time.json
+++ b/src/topics/time.json
@@ -7,9 +7,9 @@
                 "OD"
             ]
         },
-        "en": "Time",
-        "fi": "Aika",
-        "nl": "De tijd"
+        "en": "time",
+        "fi": "aika",
+        "nl": "de tijd"
     },
     "now": {
         "level": {
@@ -19,9 +19,9 @@
                 "OD"
             ]
         },
-        "en": "Now",
-        "fi": "Nyt",
-        "nl": "Nu"
+        "en": "now",
+        "fi": "nyt",
+        "nl": "nu"
     },
     "morning": {
         "level": {
@@ -32,14 +32,14 @@
             ]
         },
         "singular": {
-            "en": "Morning",
-            "fi": "Aamu",
-            "nl": "De ochtend"
+            "en": "morning",
+            "fi": "aamu",
+            "nl": "de ochtend"
         },
         "plural": {
-            "en": "Mornings",
-            "fi": "Aamut",
-            "nl": "De ochtenden"
+            "en": "mornings",
+            "fi": "aamut",
+            "nl": "de ochtenden"
         }
     },
     "noon": {
@@ -56,12 +56,12 @@
             ]
         },
         "singular": {
-            "en": "Noon",
-            "fi": "Keskipäivä",
-            "nl": "Twaalf uur 's middags"
+            "en": "noon",
+            "fi": "keskipäivä",
+            "nl": "twaalf uur 's middags"
         },
         "plural": {
-            "fi": "Keskipäivät"
+            "fi": "keskipäivät"
         }
     },
     "afternoon": {
@@ -77,14 +77,14 @@
             "nl": "day"
         },
         "singular": {
-            "en": "Afternoon",
-            "fi": "Iltapäivä",
-            "nl": "De middag"
+            "en": "afternoon",
+            "fi": "iltapäivä",
+            "nl": "de middag"
         },
         "plural": {
-            "en": "Afternoons",
-            "fi": "Iltapäivät",
-            "nl": "De middagen"
+            "en": "afternoons",
+            "fi": "iltapäivät",
+            "nl": "de middagen"
         }
     },
     "evening": {
@@ -96,14 +96,14 @@
             ]
         },
         "singular": {
-            "en": "Evening",
-            "fi": "Ilta",
-            "nl": "De avond"
+            "en": "evening",
+            "fi": "ilta",
+            "nl": "de avond"
         },
         "plural": {
-            "en": "Evenings",
-            "fi": "Illat",
-            "nl": "De avonden"
+            "en": "evenings",
+            "fi": "illat",
+            "nl": "de avonden"
         }
     },
     "night": {
@@ -115,14 +115,14 @@
             ]
         },
         "singular": {
-            "en": "Night",
-            "fi": "Yö",
-            "nl": "De nacht"
+            "en": "night",
+            "fi": "yö",
+            "nl": "de nacht"
         },
         "plural": {
-            "en": "Nights",
-            "fi": "Yöt",
-            "nl": "De nachten"
+            "en": "nights",
+            "fi": "yöt",
+            "nl": "de nachten"
         }
     },
     "midnight": {
@@ -132,14 +132,14 @@
         },
         "roots": "night",
         "singular": {
-            "en": "Midnight",
-            "fi": "Keskiyö",
-            "nl": "De middernacht"
+            "en": "midnight",
+            "fi": "keskiyö",
+            "nl": "de middernacht"
         },
         "plural": {
-            "en": "Midnights",
-            "fi": "Keskiyöt",
-            "nl": "De middernachten"
+            "en": "midnights",
+            "fi": "keskiyöt",
+            "nl": "de middernachten"
         }
     },
     "year": {
@@ -151,14 +151,14 @@
             ]
         },
         "singular": {
-            "en": "Year",
-            "fi": "Vuosi",
-            "nl": "Het jaar"
+            "en": "year",
+            "fi": "vuosi",
+            "nl": "het jaar"
         },
         "plural": {
-            "en": "Years",
-            "fi": "Vuodet",
-            "nl": "De jaren"
+            "en": "years",
+            "fi": "vuodet",
+            "nl": "de jaren"
         }
     },
     "decade": {
@@ -173,14 +173,14 @@
             ]
         },
         "singular": {
-            "en": "Decade",
-            "fi": "Vuosikymmen",
-            "nl": "Het decennium"
+            "en": "decade",
+            "fi": "vuosikymmen",
+            "nl": "het decennium"
         },
         "plural": {
-            "en": "Decades",
-            "fi": "Vuosikymmenet",
-            "nl": "De decennia"
+            "en": "decades",
+            "fi": "vuosikymmenet",
+            "nl": "de decennia"
         }
     },
     "century": {
@@ -195,14 +195,14 @@
             ]
         },
         "singular": {
-            "en": "Century",
-            "fi": "Vuosisata",
-            "nl": "De eeuw"
+            "en": "century",
+            "fi": "vuosisata",
+            "nl": "de eeuw"
         },
         "plural": {
-            "en": "Centuries",
-            "fi": "Vuosisadat",
-            "nl": "De eeuwen"
+            "en": "centuries",
+            "fi": "vuosisadat",
+            "nl": "de eeuwen"
         }
     },
     "hour": {
@@ -214,14 +214,14 @@
             ]
         },
         "singular": {
-            "en": "Hour",
-            "fi": "Tunti",
-            "nl": "Het uur"
+            "en": "hour",
+            "fi": "tunti",
+            "nl": "het uur"
         },
         "plural": {
-            "en": "Hours",
-            "fi": "Tunnit",
-            "nl": "De uren"
+            "en": "hours",
+            "fi": "tunnit",
+            "nl": "de uren"
         }
     },
     "minute": {
@@ -233,14 +233,14 @@
             ]
         },
         "singular": {
-            "en": "Minute",
-            "fi": "Minuutti",
-            "nl": "De minuut"
+            "en": "minute",
+            "fi": "minuutti",
+            "nl": "de minuut"
         },
         "plural": {
-            "en": "Minutes",
-            "fi": "Minuutit",
-            "nl": "De minuten"
+            "en": "minutes",
+            "fi": "minuutit",
+            "nl": "de minuten"
         }
     },
     "clock": {
@@ -252,14 +252,14 @@
             ]
         },
         "singular": {
-            "en": "Clock",
-            "fi": "Kello",
-            "nl": "De klok"
+            "en": "clock",
+            "fi": "kello",
+            "nl": "de klok"
         },
         "plural": {
-            "en": "Clocks",
-            "fi": "Kelloja",
-            "nl": "De klokken"
+            "en": "clocks",
+            "fi": "kelloja",
+            "nl": "de klokken"
         }
     },
     "what time is it": {
diff --git a/src/topics/transport.json b/src/topics/transport.json
index 004cf47b..cb659b96 100644
--- a/src/topics/transport.json
+++ b/src/topics/transport.json
@@ -8,14 +8,30 @@
             ]
         },
         "singular": {
-            "en": "Car",
-            "fi": "Auto",
-            "nl": "De auto"
+            "en": "car",
+            "fi": "auto",
+            "nl": "de auto"
         },
         "plural": {
-            "en": "Cars",
-            "fi": "Autot",
-            "nl": "De auto's"
+            "en": "cars",
+            "fi": "autot",
+            "nl": "de auto's"
+        }
+    },
+    "elevator": {
+        "level": {
+            "B1": "OD",
+            "none": "EP"
+        },
+        "singular": {
+            "en": ["elevator", "lift"],
+            "fi": "hissi",
+            "nl": "de lift"
+        },
+        "plural": {
+            "en": ["elevators", "lifts"],
+            "fi": "hissit",
+            "nl": "de liften"
         }
     }
 }
\ No newline at end of file
diff --git a/src/topics/verbs.json b/src/topics/verbs.json
index ff2e9f59..b9d8e0c2 100644
--- a/src/topics/verbs.json
+++ b/src/topics/verbs.json
@@ -10,9 +10,9 @@
         "declarative": {
             "affirmative": {
                 "infinitive": {
-                    "en": "To be",
-                    "fi": "Olla",
-                    "nl": "Zijn"
+                    "en": "to be",
+                    "fi": "olla",
+                    "nl": "zijn"
                 },
                 "present tense": {
                     "singular": {
@@ -421,9 +421,9 @@
         "declarative": {
             "affirmative": {
                 "infinitive": {
-                    "en": "To have",
-                    "fi": "Olla;omistaa",
-                    "nl": "Hebben"
+                    "en": "to have",
+                    "fi": "olla;omistaa",
+                    "nl": "hebben"
                 },
                 "present tense": {
                     "singular": {
@@ -872,9 +872,9 @@
             ]
         },
         "infinitive": {
-            "en": "To paint",
-            "fi": "Maalata",
-            "nl": "Schilderen"
+            "en": "to paint",
+            "fi": "maalata",
+            "nl": "schilderen"
         },
         "present tense": {
             "singular": {
@@ -972,9 +972,9 @@
             ]
         },
         "infinitive": {
-            "en": "To walk",
-            "fi": "Kävellä",
-            "nl": "Lopen"
+            "en": "to walk",
+            "fi": "kävellä",
+            "nl": "lopen"
         },
         "present tense": {
             "singular": {
@@ -1071,9 +1071,9 @@
             ]
         },
         "infinitive": {
-            "en": "To run",
-            "fi": "Juosta",
-            "nl": "Rennen"
+            "en": "to run",
+            "fi": "juosta",
+            "nl": "rennen"
         },
         "present tense": {
             "singular": {
@@ -1171,9 +1171,9 @@
             ]
         },
         "infinitive": {
-            "en": "To eat",
-            "fi": "Syödä",
-            "nl": "Eten"
+            "en": "to eat",
+            "fi": "syödä",
+            "nl": "eten"
         },
         "present tense": {
             "singular": {
@@ -1271,9 +1271,9 @@
             ]
         },
         "infinitive": {
-            "en": "To sleep",
-            "fi": "Nukkua",
-            "nl": "Slapen"
+            "en": "to sleep",
+            "fi": "nukkua",
+            "nl": "slapen"
         },
         "present tense": {
             "singular": {
@@ -1371,9 +1371,9 @@
             ]
         },
         "infinitive": {
-            "en": "To go",
-            "fi": "Mennä",
-            "nl": "Gaan"
+            "en": "to go",
+            "fi": "mennä",
+            "nl": "gaan"
         },
         "present tense": {
             "singular": {
@@ -1470,9 +1470,9 @@
             ]
         },
         "infinitive": {
-            "en": "To come",
-            "fi": "Tulla",
-            "nl": "Komen"
+            "en": "to come",
+            "fi": "tulla",
+            "nl": "komen"
         },
         "present tense": {
             "singular": {
@@ -1570,9 +1570,9 @@
             ]
         },
         "infinitive": {
-            "en": "To read",
-            "fi": "Lukea",
-            "nl": "Lezen"
+            "en": "to read",
+            "fi": "lukea",
+            "nl": "lezen"
         },
         "present tense": {
             "singular": {
@@ -1670,9 +1670,9 @@
             ]
         },
         "infinitive": {
-            "en": "To write",
-            "fi": "Kirjoittaa",
-            "nl": "Schrijven"
+            "en": "to write",
+            "fi": "kirjoittaa",
+            "nl": "schrijven"
         },
         "present tense": {
             "singular": {
@@ -1770,9 +1770,9 @@
             ]
         },
         "infinitive": {
-            "en": "To live",
-            "fi": "Asua",
-            "nl": "Wonen"
+            "en": "to live",
+            "fi": "asua",
+            "nl": "wonen"
         },
         "present tense": {
             "singular": {
diff --git a/src/topics/weather.json b/src/topics/weather.json
index cdf0d740..8a8b0381 100644
--- a/src/topics/weather.json
+++ b/src/topics/weather.json
@@ -6,9 +6,9 @@
                 "OD"
             ]
         },
-        "en": "Weather",
-        "fi": "Sää",
-        "nl": "Het weer"
+        "en": "weather",
+        "fi": "sää",
+        "nl": "het weer"
     },
     "how is the weather": {
         "roots": {
@@ -42,9 +42,9 @@
                 "OD"
             ]
         },
-        "en": "Rain",
-        "fi": "Sade",
-        "nl": "De regen"
+        "en": "rain",
+        "fi": "sade",
+        "nl": "de regen"
     },
     "sun": {
         "level": {
@@ -54,9 +54,9 @@
                 "OD"
             ]
         },
-        "en": "Sun",
-        "fi": "Aurinko",
-        "nl": "De zon"
+        "en": "sun",
+        "fi": "aurinko",
+        "nl": "de zon"
     },
     "wind": {
         "level": {
@@ -66,9 +66,9 @@
             ],
             "A2": "OD"
         },
-        "en": "Wind",
-        "fi": "Tuuli",
-        "nl": "De wind"
+        "en": "wind",
+        "fi": "tuuli",
+        "nl": "de wind"
     },
     "cloud": {
         "level": {
@@ -78,14 +78,14 @@
             ]
         },
         "singular": {
-            "en": "Cloud",
-            "fi": "Pilvi",
-            "nl": "De wolk"
+            "en": "cloud",
+            "fi": "pilvi",
+            "nl": "de wolk"
         },
         "plural": {
-            "en": "Clouds",
-            "fi": "Pilvet",
-            "nl": "De wolken"
+            "en": "clouds",
+            "fi": "pilvet",
+            "nl": "de wolken"
         }
     },
     "snow": {
@@ -95,18 +95,18 @@
                 "OD"
             ]
         },
-        "en": "Snow",
-        "fi": "Lumi",
-        "nl": "De sneeuw"
+        "en": "snow",
+        "fi": "lumi",
+        "nl": "de sneeuw"
     },
     "ice": {
         "level": {
             "A1": "OD",
             "A2": "EP"
         },
-        "en": "Ice",
-        "fi": "Jää",
-        "nl": "Het ijs"
+        "en": "ice",
+        "fi": "jää",
+        "nl": "het ijs"
     },
     "storm": {
         "level": {
@@ -115,27 +115,27 @@
                 "OD"
             ]
         },
-        "en": "Storm",
-        "fi": "Myrsky",
-        "nl": "De storm"
+        "en": "storm",
+        "fi": "myrsky",
+        "nl": "de storm"
     },
     "thunder": {
         "level": {
             "B1": "EP",
             "C1": "OD"
         },
-        "en": "Thunder",
-        "fi": "Ukkonen",
-        "nl": "De donder"
+        "en": "thunder",
+        "fi": "ukkonen",
+        "nl": "de donder"
     },
     "fog": {
         "level": {
             "A2": "EP",
             "B2": "OD"
         },
-        "en": "Fog",
-        "fi": "Sumu",
-        "nl": "De mist"
+        "en": "fog",
+        "fi": "sumu",
+        "nl": "de mist"
     },
     "rainy": {
         "level": {
@@ -143,9 +143,9 @@
             "B1": "EP"
         },
         "roots": "rain",
-        "en": "Rainy",
-        "fi": "Sateinen",
-        "nl": "Regenachtig"
+        "en": "rainy",
+        "fi": "sateinen",
+        "nl": "regenachtig"
     },
     "sunny": {
         "level": {
@@ -153,9 +153,9 @@
             "A2": "EP"
         },
         "roots": "sun",
-        "en": "Sunny",
-        "fi": "Aurinkoinen",
-        "nl": "Zonnig"
+        "en": "sunny",
+        "fi": "aurinkoinen",
+        "nl": "zonnig"
     },
     "windy": {
         "level": {
@@ -165,9 +165,9 @@
             ]
         },
         "roots": "wind",
-        "en": "Windy",
-        "fi": "Tuulinen",
-        "nl": "Winderig"
+        "en": "windy",
+        "fi": "tuulinen",
+        "nl": "winderig"
     },
     "cloudy": {
         "level": {
@@ -175,9 +175,9 @@
             "B1": "OD"
         },
         "roots": "cloud",
-        "en": "Cloudy",
-        "fi": "Pilvinen",
-        "nl": "Bewolkt"
+        "en": "cloudy",
+        "fi": "pilvinen",
+        "nl": "bewolkt"
     },
     "snowy": {
         "level": {
@@ -185,9 +185,9 @@
             "none": "EP"
         },
         "roots": "snow",
-        "en": "Snowy",
-        "fi": "Luminen",
-        "nl": "Besneeuwd"
+        "en": "snowy",
+        "fi": "luminen",
+        "nl": "besneeuwd"
     },
     "stormy": {
         "level": {
@@ -197,9 +197,9 @@
             ]
         },
         "roots": "storm",
-        "en": "Stormy",
-        "fi": "Myrskyinen",
-        "nl": "Stormachtig"
+        "en": "stormy",
+        "fi": "myrskyinen",
+        "nl": "stormachtig"
     },
     "there is a thunderstorm": {
         "roots": {
@@ -227,9 +227,9 @@
             "OD": "B2"
         },
         "roots": "fog",
-        "en": "Foggy",
-        "fi": "Sumuinen",
-        "nl": "Mistig"
+        "en": "foggy",
+        "fi": "sumuinen",
+        "nl": "mistig"
     },
     "it is raining": {
         "roots": {


Test patch:
diff --git a/tests/base.py b/tests/base.py
index 794c3f9f..f287fade 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -31,7 +31,7 @@ def create_quiz(  # noqa: PLR0913
         answer_language: str,
         question: str,
         answers: list[str],
-        quiz_type: str | tuple[str] = "translate",
+        quiz_type: str | tuple[str, ...] = "translate",
         blocked_by: tuple[Quiz, ...] = tuple(),
         meanings: tuple[str, ...] = tuple(),
     ) -> Quiz:
@@ -47,3 +47,25 @@ def create_quiz(  # noqa: PLR0913
             blocked_by,
             Labels(Label(meaning) for meaning in meanings),
         )
+
+    @classmethod
+    def copy_quiz(  # noqa: PLR0913
+        cls,
+        quiz: Quiz,
+        question_language: str = "",
+        answer_language: str = "",
+        question: str = "",
+        answers: list[str] | None = None,
+        quiz_type: str | tuple[str, ...] = "",
+    ) -> Quiz:
+        """Copy the quiz, overriding some of its parameters."""
+        return cls.create_quiz(
+            quiz.concept,
+            question_language or quiz.question_language,
+            answer_language or quiz.answer_language,
+            question or quiz.question,
+            answers or [str(answer) for answer in quiz.answers],
+            quiz_type or tuple(str(quiz_type) for quiz_type in quiz.quiz_types),
+            quiz.blocked_by,
+            quiz.meanings,
+        )
diff --git a/tests/toisto/command/test_show_progress.py b/tests/toisto/command/test_show_progress.py
index 64c399da..0cbfaccc 100644
--- a/tests/toisto/command/test_show_progress.py
+++ b/tests/toisto/command/test_show_progress.py
@@ -31,7 +31,7 @@ def test_quiz(self):
         start = (now - timedelta(hours=1)).isoformat(timespec="seconds")
         end = now.isoformat(timespec="seconds")
         with patch("rich.console.Console.print") as console_print:
-            show_progress("fi", self.topics, Progress({self.quiz.key(): dict(start=start, end=end)}, self.topics))
+            show_progress("fi", self.topics, Progress({self.quiz.key: dict(start=start, end=end)}, self.topics))
         for index, value in enumerate(["Translate", "Terve", "fi", "nl", "Hoi", "0", "60 minutes", ""]):
             self.assertEqual(value, list(console_print.call_args[0][0].columns[index].cells)[0])
 
@@ -39,14 +39,14 @@ def test_quiz_silenced_until_time_in_the_future(self):
         """Test that if the time until which a quiz is silenced lies in the future, it is shown."""
         skip_until = (datetime.now() + timedelta(days=1)).isoformat(sep=" ", timespec="minutes")
         with patch("rich.console.Console.print") as console_print:
-            show_progress("fi", self.topics, Progress({self.quiz.key(): dict(skip_until=skip_until)}, self.topics))
+            show_progress("fi", self.topics, Progress({self.quiz.key: dict(skip_until=skip_until)}, self.topics))
         self.assertEqual(skip_until, list(console_print.call_args[0][0].columns[7].cells)[0])
 
     def test_quiz_silenced_until_time_in_the_past(self):
         """Test that if the time until which a quiz is silenced lies in the past, it is not shown."""
         skip_until = (datetime.now() - timedelta(days=1)).isoformat(sep=" ", timespec="minutes")
         with patch("rich.console.Console.print") as console_print:
-            show_progress("fi", self.topics, Progress({self.quiz.key(): dict(skip_until=skip_until)}, self.topics))
+            show_progress("fi", self.topics, Progress({self.quiz.key: dict(skip_until=skip_until)}, self.topics))
         self.assertEqual("", list(console_print.call_args[0][0].columns[7].cells)[0])
 
     def test_sort_by_retention(self):
@@ -58,7 +58,7 @@ def test_sort_by_retention(self):
         another_quiz = self.create_quiz(another_concept, "fi", "nl", "Matto", ["Het tapijt"])
         topics = Topics({Topic("topic", (), {self.quiz, another_quiz})})
         progress = Progress(
-            {self.quiz.key(): dict(count=21, start=start, end=end), another_quiz.key(): dict(count=42)},
+            {self.quiz.key: dict(count=21, start=start, end=end), another_quiz.key: dict(count=42)},
             self.topics,
         )
         with patch("rich.console.Console.print") as console_print:
diff --git a/tests/toisto/model/quiz/test_progress.py b/tests/toisto/model/quiz/test_progress.py
index 8c2b16a3..4d65bbbd 100644
--- a/tests/toisto/model/quiz/test_progress.py
+++ b/tests/toisto/model/quiz/test_progress.py
@@ -42,6 +42,12 @@ def test_update_progress_incorrect(self):
         self.assertIsNone(self.progress.get_retention(self.quiz).end)
         self.assertIsNone(self.progress.get_retention(self.quiz).skip_until)
 
+    def test_update_progress_when_case_changed(self):
+        """Test that changing the case of labels does impact the progress."""
+        self.progress.increase_retention(self.quiz)
+        quiz_with_case_changed = self.copy_quiz(self.quiz, question=self.quiz.question.lower())
+        self.assertNotEqual(self.progress.get_retention(self.quiz), self.progress.get_retention(quiz_with_case_changed))
+
     def test_next_quiz(self):
         """Test that the next quiz is not silenced."""
         progress = self.create_progress({self.quiz, self.another_quiz})
diff --git a/tests/toisto/model/quiz/test_quiz.py b/tests/toisto/model/quiz/test_quiz.py
index 90571c4c..fbe9f823 100644
--- a/tests/toisto/model/quiz/test_quiz.py
+++ b/tests/toisto/model/quiz/test_quiz.py
@@ -106,34 +106,34 @@ class QuizEqualityTests(QuizTestCase):
     def test_equal(self):
         """Test that a quiz is equal to itself and to quizzes with the same parameters."""
         self.assertEqual(self.quiz, self.quiz)
-        same_quiz = self.create_quiz(self.concept, "fi", "nl", "Englanti", ["Engels"])
-        self.assertEqual(same_quiz, self.quiz)
+        self.assertEqual(self.copy_quiz(self.quiz), self.quiz)
 
     def test_equal_with_different_hints(self):
         """Test that quizzes are equal if only their hints differ."""
-        different_answer_hint = self.create_quiz(self.concept, "fi", "nl", "Englanti;hint", ["Engels"])
-        self.assertEqual(different_answer_hint, self.quiz)
-        different_question_hint = self.create_quiz(self.concept, "fi", "nl", "Englanti", ["Engels;hint"])
-        self.assertEqual(different_question_hint, self.quiz)
+        self.assertEqual(self.copy_quiz(self.quiz, question="Englanti;hint"), self.quiz)
+        self.assertEqual(self.copy_quiz(self.quiz, answers=["Engels;hint"]), self.quiz)
 
     def test_not_equal_with_different_languages(self):
         """Test that quizzes are not equal if only their languages differ."""
-        different_question_language = self.create_quiz(self.concept, "en", "nl", "Englanti", ["Engels"])
-        self.assertNotEqual(different_question_language, self.quiz)
-        different_answer_language = self.create_quiz(self.concept, "fi", "en", "Englanti", ["Engels"])
-        self.assertNotEqual(different_answer_language, self.quiz)
+        self.assertNotEqual(self.copy_quiz(self.quiz, question_language="nl"), self.quiz)
+        self.assertNotEqual(self.copy_quiz(self.quiz, answer_language="en"), self.quiz)
 
     def test_not_equal_with_different_questions(self):
         """Test that quizzes are not equal if only their questions differ."""
-        different_question = self.create_quiz(self.concept, "fi", "nl", "Saksa", ["Engels"])
-        self.assertNotEqual(different_question, self.quiz)
+        self.assertNotEqual(self.copy_quiz(self.quiz, question="Saksa"), self.quiz)
 
     def test_equal_with_different_answers(self):
         """Test that quizzes are equal if only their answers differ."""
-        different_answers = self.create_quiz(self.concept, "fi", "nl", "Englanti", ["Duits"])
-        self.assertEqual(different_answers, self.quiz)
+        self.assertEqual(self.copy_quiz(self.quiz, answers=["Duits"]), self.quiz)
 
     def test_not_equal_with_different_quiz_types(self):
         """Test that quizzes are not equal if only their quiz types differ."""
-        different_quiz_type = self.create_quiz(self.concept, "fi", "nl", "Englanti", ["Engels"], "listen")
-        self.assertNotEqual(different_quiz_type, self.quiz)
+        self.assertNotEqual(self.copy_quiz(self.quiz, quiz_type="listen"), self.quiz)
+
+    def test_not_equal_when_questions_have_different_case(self):
+        """Test that quizzes are different if only the case of the question differs."""
+        self.assertNotEqual(self.copy_quiz(self.quiz, question=self.quiz.question.lower()), self.quiz)
+
+    def test_equal_when_answers_have_different_case(self):
+        """Test that quizzes are equal if only the case of the answers differs."""
+        self.assertEqual(self.copy_quiz(self.quiz, answers=[answer.lower() for answer in self.quiz.answers]), self.quiz)
diff --git a/tests/toisto/persistence/test_topics.py b/tests/toisto/persistence/test_topics.py
index dbf32a48..601f8c71 100644
--- a/tests/toisto/persistence/test_topics.py
+++ b/tests/toisto/persistence/test_topics.py
@@ -40,3 +40,18 @@ def test_load_topic_by_filename(self, stderr_write: Mock):
             "cannot read topic file-doesnt-exist: [Errno 2] No such file or directory: 'file-doesnt-exist'.\n",
             stderr_write.call_args_list[1][0][0],
         )
+
+    @patch("pathlib.Path.exists", Mock(return_value=True))
+    @patch("pathlib.Path.open")
+    @patch("sys.stderr.write")
+    def test_load_topics_with_same_concept_id(self, stderr_write: Mock, path_open: Mock):
+        """Test that an error message is given when a topic file contains the same concept id as another topic file."""
+        path_open.return_value.__enter__.return_value.read.side_effect = [
+            '{"concept_id": {"fi": "label1", "nl": "Label2"}}\n',
+            '{"concept_id": {"fi": "Label3", "nl": "Label4"}}\n',
+        ]
+        self.assertRaises(SystemExit, load_topics, "fi", "nl", [], [], ["file1", "file2"], ArgumentParser())
+        self.assertIn(
+            "Toisto cannot read topic file2: concept identifier 'concept_id' also occurs in topic 'file1'.\n",
+            stderr_write.call_args_list[1][0][0],
+        )
diff --git a/tests/toisto/test_app.py b/tests/toisto/test_app.py
index 3c736499..07e4be0d 100644
--- a/tests/toisto/test_app.py
+++ b/tests/toisto/test_app.py
@@ -7,6 +7,7 @@
 import requests
 from toisto.app import main
 from toisto.metadata import VERSION
+from toisto.model.language.concept import Concept
 
 
 class AppTest(unittest.TestCase):
@@ -14,19 +15,21 @@ class AppTest(unittest.TestCase):
 
     def setUp(self):
         """Set up test fixtures."""
+        Concept.instances = {}
         self.latest_version = Mock(json=Mock(return_value=[dict(name="v9999")]))
 
     @patch("os.system", Mock())
     @patch("builtins.input", Mock(side_effect=EOFError))
+    @patch("pathlib.Path.exists", Mock(return_value=True))
     @patch("pathlib.Path.open")
     def run_main(self, path_open: Mock) -> Mock:
         """Run the main function and return the patched print method."""
-        path_open.return_value.__enter__.return_value.read.return_value = '{"bad": {"fi": "Huono"}}\n'
+        path_open.return_value.__enter__.return_value.read.return_value = '{"xxx": {"nl": "XXX", "fi": "YYY"}}\n'
         with patch("rich.console.Console.print") as patched_print:
             main()
         return patched_print
 
-    @patch.object(sys, "argv", ["toisto", "practice", "--target", "fi", "--source", "nl"])
+    @patch.object(sys, "argv", ["toisto", "practice", "--target", "fi", "--source", "nl", "--topic-file", "test"])
     @patch("requests.get")
     def test_practice(self, requests_get: Mock):
         """Test that the practice command can be invoked."""
@@ -34,7 +37,7 @@ def test_practice(self, requests_get: Mock):
         patched_print = self.run_main()
         self.assertTrue(patched_print.call_args_list[2][0][0].startswith("👋 Welcome to [underline]Toisto"))
 
-    @patch.object(sys, "argv", ["toisto", "practice", "--target", "fi", "--source", "nl"])
+    @patch.object(sys, "argv", ["toisto", "practice", "--target", "fi", "--source", "nl", "--topic-file", "test"])
     @patch("requests.get")
     def test_new_version(self, requests_get: Mock):
         """Test that the practice command shows a new version."""
@@ -42,7 +45,7 @@ def test_new_version(self, requests_get: Mock):
         patched_print = self.run_main()
         self.assertTrue("v9999" in patched_print.call_args_list[3][0][0].renderable)
 
-    @patch.object(sys, "argv", ["toisto", "practice", "--target", "fi", "--source", "nl"])
+    @patch.object(sys, "argv", ["toisto", "practice", "--target", "fi", "--source", "nl", "--topic-file", "test"])
     @patch("requests.get")
     def test_current_version(self, requests_get: Mock):
         """Test that the practice command does not show the current version."""
@@ -50,7 +53,7 @@ def test_current_version(self, requests_get: Mock):
         patched_print = self.run_main()
         self.assertTrue("[quiz]" in patched_print.call_args_list[3][0][0])
 
-    @patch.object(sys, "argv", ["toisto", "practice", "--target", "fi", "--source", "nl"])
+    @patch.object(sys, "argv", ["toisto", "practice", "--target", "fi", "--source", "nl", "--topic-file", "test"])
     @patch("requests.get")
     def test_github_connection_error(self, requests_get: Mock):
         """Test that the practice command starts even if GitHub cannot be reached to get the latest version."""
@@ -58,7 +61,7 @@ def test_github_connection_error(self, requests_get: Mock):
         patched_print = self.run_main()
         self.assertTrue(patched_print.call_args_list[2][0][0].startswith("👋 Welcome to [underline]Toisto"))
 
-    @patch.object(sys, "argv", ["toisto", "progress", "--target", "fi", "--source", "nl"])
+    @patch.object(sys, "argv", ["toisto", "progress", "--target", "fi", "--source", "nl", "--topic-file", "test"])
     @patch("requests.get")
     def test_progress(self, requests_get: Mock):
         """Test that the progress command can be invoked."""
@@ -66,7 +69,7 @@ def test_progress(self, requests_get: Mock):
         patched_print = self.run_main()
         self.assertTrue(patched_print.call_args_list[2][0][0].title.startswith("Progress"))
 
-    @patch.object(sys, "argv", ["toisto", "topics", "--target", "fi", "--source", "nl"])
+    @patch.object(sys, "argv", ["toisto", "topics", "--target", "fi", "--source", "nl", "--topic-file", "test"])
     @patch("requests.get")
     def test_topics(self, requests_get: Mock):
         """Test that the topics command can be invoked."""