D anish in W ikidata lexemes (2019)

Abstract: Wikidata introduced support for lexicographic data in 2018. Here we describe the lexicographic part of Wikidata as well as experiences with setting up lexemes for the Danish language. We note various possible annotations for lexemes as well as discuss various choices made.

## introduction wikipedia's structured sister wikidata (vrandečić and krötzsch, 2014) at https://www.wikidata. org/ supports interlinking different language versions of wikipedia as well as several other wikimedia sites, such as wikibooks and wikimedia commons. one wiki that has been missing from the list is wiktionary, -the dictionary wiki. wiktionary has a structure different from the other wikis as multiple different words and concepts might be described on the same page, only connected through the same orthographic representation. in 2018, wikidata enabled support for lexicographic data via special lexeme wiki pages. compared to wiktionary, wikidata lexemes offer a solution with directly machine-readable data: it is not necessary to write parsers to obtain the lexeme data in a structured format. wikidata lexemes also reduce the amount of redundant input: in wiktionary, each language edition sets up its own dictionary, and a word described in one wiktionary is not directly available in another wiktionary. further issues with wiktionary are the linkage to the wikidata concept ontology and the linkage to external resources such as wordnet @xcite . neither of these links is non-trivial to set up, though matching lexical entries between wiktionary and wordnet may be done with good accuracy @xcite . below we will describe how lexemes are supported on wikidata, 1 and list some of the danish resources relevant for wikidata lexemes. then we will detail how danish lexemes have been annotated and discuss some of the choices made. 1 there is an introduction to wikidata lexemes on wikidata itself at https://www.wikidata.org/wiki/ wikidata_talk:lexicographical_data . ## wikidata lexemes wikidata stores lexeme data on a new type of pages prefixed with the letter 'l' and further identified with an integer, e.g., the danish lexeme gentagelse (repetition) has the identifier "l117" and available for view and edit at https://www.wikidata.org/ wiki/lexeme:l117 . on the same page, multiple senses and forms for the lexeme may be defined. they are identified by suffixes to the lexeme identifier, e.g., the plural indefinite form gentagelser would be identified as "l117-f3", while the first sense-if it was defined-would have been identified as "l117-s1". forms and senses are defined separately, so it is currently difficult to define a specific sense for a specific form. lexemes, forms and senses may be associated with properties, and these properties are identified with integer prefixed with the letter 'p'. the wikidata lexeme data maps to an rdf representation, foot_0 and the rdf data is queryable via the wikidata query service sparql endpoint at https://query.wikidata.org/ . the mapping uses part of the lexicon model for ontologies (lemon) ontology @xcite . the central owl concepts for the lexeme data are ontolex:lexicalentry, ontolex:form and ontolex:lexicalsense for lexeme, form and sense respectively with the prefix http://www.w3.org/ns/lemon/ontolex# . each of these three owl concepts has associated basic data in wikidata. apart from the identifier, the lexeme has the lemma, language and lexical category, the form has its orthographic representation and grammatical features while the sense may have multiple glosses. this basic data cannot be associated with qualifiers and references like normal wikidata properties. links from wikidata lexemes (l-pages) to qitems (i.e., the ordinary wikidata items) are of two kinds: either for the description of the lexical and grammatical "metadata" for the lexeme or for the description of the meaning of a sense. in the latter case, the q-items function as the wordnet notion of synsets. wikidata has specific properties to link q-items to synsets in external lexical resources, including babelnet (navigli and ponzetto, 2010) (p2581) and the collaborative interlingual index (p5063) @xcite . alternatively, the more generic property for linked open data uris (p2888) can be used. wikidata has linked some wordnet synsets used in imagenet. the correspondence between the resources is not necessarily straightforward to establish @xcite . some statistics for the lexeme data in wikidata are displayed in ## annotating lexemes, forms and senses wikidata has a continuously growing number of properties that can be used to annotate lexemes, forms and senses. general properties-that are relevant for lexemes of most word classes-are usage example (p5831), word stem (p5187) and derived from (p5191), where the latter may indicate etymological origin or origin of derivations. compound parts may be linked with a property (p5238) and the order of the parts may be specified with a property used as a qualifier (p1545). the wikidata property for dannet words (p6140) are linked to version 2.2 of the resource. as of march 2019, 844 lexemes with associated information about dannet words are linked. 7 the data model of wikidata al-lows for the specification of "no value", thus it is possible to specify that a lexeme cannot be found in the dannet 2.2 resource. for instance, adverbs and rare nouns, such as lommevogn (l40687), are not in dannet and indicated as such. the usage example property (p5831) can store a short freeform text and the qualifier stated in (p248) can point to a q-item with metadata about a work forms may be associated with hyphenation and pronunciation specification. wikidata has properties for x-sampa, ipa transcription and kirshenbaum code. these pronunciation properties have been used on wikidata's q-items, but so far not (or very limited) for danish lexemes. senses can be associated with language style (p6191) and perhaps most importantly with item for this sense property (p5137) which links the senses of lexemes to the q-items and thus with the rest of the wikidata knowledge graph. synonyms, antonyms, hypernyms and hyponyms may be inferred from the information in that part of the wikidata knowledge graph. links between lexemes in different languages can currently be made with a specific translation property (p5972) applicable for senses, or the connection between lexemes can be made through their senses and the p5137 property linking to q-item that then binds lexemes from separate languages together. ## discussion wikidata is entirely field-based and especially for lexemes there are very few means to enter free-form information. while exceptions can be noted in standard dictionaries such as wiktionary, almost every piece of information added for a lexeme in wikidata must be associated with a property. the explicitness of wikidata complicates the modeling of language. below we discuss a few of the issues that have appeared for the danish language. ## related research among related research, there are several studies reporting the extraction of data from wiktionary and using the structured data for linguistic tasks or building a resource @xcite @xcite . for instance, the java-and database-based system by @xcite for reading, storing and querying lexical semantic knowledge from wikipedia and wiktionary enables a user, e.g., to programmatically query for hyponyms of senses. the parser of the described system needs to be adjusted for each language edition of wiktionary as each edition may use different markup for the lexical semantic information. the lexicographic part of wikidata is still comparably small, but contrary to many other online dictionaries with rich semantics, wikidata users can add and edit the lexicographic information and more or less immediately see it becoming available in the powerful query facility of the sparql-based wikidata query service. our ordia web application at http://tools.wmflabs. org/ordia takes advantage of this service @xcite .