Alignment of W ikidata lexemes and Det Centrale Ordregister (2023)

Abstract: Two Danish open access lexicographic resources have appeared in recent years: lexemes in Wikidata and Det Centrale Ordregister (COR). The lexeme part of Wikidata describes words in different languages and COR associates an identifier with each different form of Danish lexemes. Here I described the current state of the linking Wikidata lexemes with COR and some of the problems encountered.

## wikidata wikidata @xcite , the large collaboratively edited knowledge graph, has a special namespace for words and the first lexeme in this namespace was created in 2018 @xcite . 1 since then the number of lexemes has steadily grown. in february 2020, wikidata had over 250,000 lexemes @xcite . as of january 2023, there were over 980,000 lexemes, over 12 million forms and over 290,000 senses. wikidata records, e.g., over 213,000 german lexemes and over 16,000 danish lexemes. a lexeme in wikidata describes forms and senses with a growing set of properties. each lexeme, form, and sense has a unique identifier. an example of a property for danish lexemes is the link to words in the danish wordnet resource dannet @xcite . four templates for lucas werkmeister's wikidata lexeme forms tool 2 are so far set up to help enter danish words in wikidata: for adjectives, verbs, and common and neuter gender nouns. 1 the sumerian word for mother, https://www. wikidata.org/w/index.php?@xmath0: l1&@xmath1://lexeme-forms.toolforge.org ## det centrale ordregister det centrale ordregister (cor) @xcite is a danish lexicographic resource with an initial test dataset released in may 2022 and since then updated. the resource and its description are available at https://ordregister. dk/ . cor mostly describes the forms of lexemes and gives each form an identifier. work on the semantic part of cor is underway @xcite , but here i will not consider this part. the version of cor i consider is version 1.02 of the core cor and the 1.0 version for cor-ext. ## cor wikidata properties for linking wikidata and cor, the wikidata community has created two wikidata properties for cor identifiers: one for the lexeme and one for the form. for instance, for the wikidata lexeme sudan (l993787) the cor lemma id, level 1 identifier (p10831) is "cor.09978" while the cor form, level 1 identifiers (p10830) are "cor.09978.500.01" and "cor.09978.500.01" for the non-genitive (sudan) and the genitive (sudans) forms, respectively. the current regular expression contraint for the lexeme form is cor\.(ext\.\d{6}|\d{5}) allowing the core cor as well as the level 2 cor-ext identifiers, -and it could be extended if other resources appear. the two cor wikidata properties were created in june 2022. as of february over 2,100 cor lexemes/lemmas and over 1,800 cor forms are linked from wikidata. foot_0 around 390 danish wikidata lexemes have so far been annotated as not being present in cor. most of these lexemes are compounds. proper nouns and a few interjections comprise most of the rest. for linking wikidata and cor it is important that there is a correspondence between the items of the two resources. danish words may have spelling variants, e.g., højtaler and højttaler. in cor, they are grouped under the same lexeme and as different variants. in wikidata, spelling variants may be grouped under the same form. for instance, the english form l1347-f1 is currently listing both color and colour, separating them with different language specifications (en and en-gb). in danish, the spelling variants do not arise due to different languages and the current wikidata interface cannot handle spelling variants within the same language in one form. so far the danish lexemes in wikidata create separate forms for each spelling variants, e.g., l229388-f1 is højtaler and l229388-f2 is højttaler, making one cor spelling variant map to one wikidata form. two wikidata spelling variant forms can be linked with the symmetric alternative form property (p8530). in wikidata, we have so far followed the scheme of den danske ordbog (ddo) for danish nouns with multiple genders and use only one lexeme for these cases. for instance, øl has common and neuter versions of the noun under the same lemma in ddo. 4 in wikidata, this is also one lexeme: l39743. in cor there are two lexemes for øl: cor.45830 and cor.48125, thus in this case we get a one-to-two relationship between wikidata and cor. other examples of this type are vand and kirsebaer. cor has safran (cor.93857) also as both common and neuter gender represented with one lexeme. the indefinite form, which does not reveal the gender, has two forms in cor: cor.93857.110.01 and cor.93857.120.01. such a word often occurs in the bare form with no article or morphological gender suffix, so it may be impossible to detect the gender of the form in the context. lexeme linking will have an ambiguity in this case. the current entry in wikidata has just one (non-genitive) indefinite form. the same issue appears, e.g., for kanel (cor.57435) and druk (cor.86399). homographs that only have one gender are well-aligned between cor, wikidata, and ddo, e.g., the noun(s) fyr has 3 separate lexemes in wikidata and also has 3 separate lexemes (lem-mas) in cor. superlative may be regarded as a derivation from the positive form @xcite , but both in cor and the danish lexemes in wikidata, the superlative is forms under normal adjective lexemes that also has the positive and comparative forms. centaur nouns (danish: kentaurnominaler) are developed from verbs with an -en suffix. in both wikidata and in cor (i.e., cor-ext), they are regarded as separate lexemes, -and not a form of the verb lexeme. danish perfektum participium (adjective forms of the verb) exists in the borderland between being forms of a verb and an adjective derived from a verb @xcite . so should perfektum participium forms be grouped under a separate lexeme? cor does usually not record the adjective form of the verb separate from the verb. for instance, barberet in et barberet ansigt (a shaved face, cor.38323.213.01) is grouped under the verb barbere (cor.38323). there is an advantage in making a derived lexeme for the adjective forms, as it allows for the description of the sense, e.g., for barberet the antonym ubarberet can be specified. in wikidata, the sense of the adjective barberet (l940943) is linked via the antonym property (p5974) to the sense of ubarberet (l940942) and vice versa. if the adjective was not a separate lexeme, but just part of the verb lexeme, it would not be straightforward to make this antonym link. with the adjective barberet as an individual lexeme, words such as glatbarberet and nybarberet becomes compounds, and the senses of the two compounds can be linked to the sense of barberet via the hypernym property. in cor, it is not all verb-derived -et adjectives that are not separated from a corresponding verb, e.g., snobbet (cor.24113) is separate from the verb snobbe (cor.37973). in these cases, the verb still has the perfektum participium forms. surprisingly, overstimulere is in cor as a verb (cor.32555) and overstimuleret is not in cor as a separate adjective, while understimulere is not in cor, while understimuleret is a separate adjective (cor.23107). adverbs from adjectives are grouped under the adjective lexeme in cor. in wikidata, lexemes must be associated with a single lexical category (e.g., adverb or adjective). we have created separate lexemes for danish adverbs from adjectives in wikidata (for the few entered so far), e.g., the adverb hurtigt with forms hurtig, hurtigere and hurtigst has the wikidata lexeme identifier (l691405) that is separate from the adjective lexeme (l42201) and with the cor lemma identifier (cor.15444) duplicated between the two wikidata items. ## lexical categories below i will go through some of the most important lexical categories and how wikidata and cor aligns. small lexical categories such as conjunctions and prepositions are fully linked, with a few oddities: ddo and wikidata have dels as a conjunction. it is an adverb in cor. wikidata has plus at as a conjunction. it does not exist in cor. ## semantics a few of the entries in cor have a short text for disambiguation of homographs. in a few cases it has been used as a gloss to the sense of a wikidata lexeme, e.g., for aeg cor disambiguates with "fx: fugleaeg" (e.g., bird's egg) and "skarp kant" (sharp edge) for the two homographs and the wikidata sense l39239-s1 "skarp kant" has been noted as a gloss referencing cor. for the other homograph, wikidata has currently two senses (biological egg and egg as food) making the application of the disambiguation text as a sense gloss difficult. such a case is not uncommon making automated setup or alignment of senses based the cor disambiguation text not feasible or at least difficult. ## discussion there are wikidata tools for mass-entry of lexemes and with cor data danish wikidata lexemes could be set up en masse. so far i have setup the links manually exploring the problems of ontology linking the two resources. i find perfektum participium, inflections of adjectives and nouns with both neuter and common gender are among the issues where one should be careful with matching. after the publication of cor, we have changed the entry of genitive for nouns and numerals and passive forms of verbs in wikidata. i suspect that we might see a revision of inflections of adjectives in cor around comparative and superlative forms.