# Text Analysis Methods for Misinformation-Related Research on Finnish Language Twitter
## 3 Materials and Methods
### Methodology Issues Related to the Language Used  
The Finnish language is a member of the Finno-Ugric language family and closely related to Estonian. In 1997, Finnish was the native language of 92.7% of Finland's population of 5.15 million people. The Finnish language does not have grammatical gender or articles. The basic principle of word formation in Finnish is the addition of endings (bound morphemes, suffixes) to stems. Furthermore, Finnish verb forms are built up in the same way. Often, the endings are piled up one behind the other rather mechanically. The adding of endings to a stem is a morphological feature of many European languages, but Finnish is nevertheless different from most others in two respects: (1) English nouns have only one \"morphologically marked\" case, but Finnish has more case endings than is usual in European languages--about 15 cases (nominative, accusative, genitive, partitive, inessive, relative, illative, adessive, ablative, allative, assive, translative, abessive, comitative, and instructive). Finnish endings normally correspond to the prepositions or postpositions in other languages; (2) Finnish sometimes uses endings, where Indo-European languages generally have independent words. For example, cases in the Finnish noun \"auto\" (\"car\" in English) is formed with the endings: auto/ssa, (\"in the car\"), auto/sta (\"out of the car\"), auto/on (\"into the car\"), auto/lla (\"by car\"), and by attaching the plural ending -I, as in auto/i/ssa (\"in the cars\"). Finnish possessive suffixes correspond to possessive pronouns, such as -ni (\"my\"), -si (\"your\"), -mme (\"our\")--for example, auto/ssa/ni (\"in my car\"), auto/ssa/si (\"in your car\"), auto/ssa/mme (\"in our car\"). An example of using the verb stem sano- (\"say\") and the endings -n (\"I\"), -i (past tense), and -han (for emphasis), verbs can be formed: sano/n (\"I say\"), sano/n/han (\"I do say\"), sano/i/n (\"I said\"), and sano/i/n/han (\"I did say\"). Another set of endings particular to Finnish is that of the enclitic particles, which always occur in the final position after all other endings, used mainly for emphasis: -kin (\"too\", \"also\") auto/ssa/si/kin (\"in your car too\"), -han (for emphasis: \"you know, don't you?\"), and -ko (English interrogative): On/ko tuo auto? (\"Is that a car?\"). Moreover, a characteristic feature of Finnish is the wide-ranging use of endings to form new words. For example, kirja (\"book\") and its derived forms kirj/e (\"letter\"), kirja/sto (\"library\"), kirja/llinen (\"literary\"), kirja/llis/uus (\"literature\"), kirjo/ita(a) (\"(to) write\"), and kirjo/ita/ja (\"writer\"). When adjectives occur as attributes, they agree in number and case with the headword, i.e., they take the same endings--for example, isossa autossa (\"in the big car\") [36]. There are two ways to form new words from existing words and stems in Finnish: (1) derivation and (2) compounding. In derivation, new words (word stems) are made by adding derivative endings or suffixes to the root or another stem, e.g., to adjective kaunis: kaunii- (\"beautiful\"), add the ending -ta to form the derived verb stem kaunis/ta(\"beautiful\"), the first infinitive kaunis/ta. Similarly, to the verb stem aja- (\"drive\"), add the ending -o to form the derived noun aj/o (\"drive\", \"chase\", \"hunt\") or the ending -ele- to form the verb stem aj/ele- (\"drive around\"), the first infinitive aj/el/la. The most common type of compound word is made up of two non-derived nouns, and typical compounds are written without spaces, e.g., autokauppa (\"car sales\"). The first noun in these compounds is often in the genitive, e.g., auto/n/ikkuna (\"car window\") [36]. In text analytics, many research projects rely on software libraries--such as the Natural Language Toolkit (NLTK)--that provide functionalities for language processing, e.g., stemmers and sentence tokenizers [37]. However, as outlined above, Finnish language stemming often leads to word stems that are not valid words, e.g., \"kirj\" but are also meaningless.