Towards a Derivational Semantics Resource for Latvian (2025)

Abstract: In this paper we describe the implementation of the first structured resource of semantic derivational links for Latvian, basing it on the largest online dictionary Tēzaurs.lv and linking it to the Latvian WordNet. We separate two kinds of derivational links: semantic derivation links between senses and morphological derivation links between lexemes. The semantic links between senses are defined as a pair of semantic labels assigned to both ends of the link. The process of semantic linking involves revising the sense inventory of both the base word and the derivative, defining semantic labels for lexemes of four basic word classes – nouns, verbs, adjectives and adverbs, and adding the appropriate labels to the corresponding senses. We exemplify our findings with a detailed representation of sense relations between a base verb and its nominal derivatives.

## introduction so far, no derivational semantics resource has been created for the latvian language. the idea for its creation grew out of the desire to extend the latvian wordnet @xcite because regular derivatives are an essential part of the lexicon, and they also have semantic relations both with their base words and with each other, for example, two derivatives can be synonyms. latvian wordnet is planned to be supplemented with derivational links, similar to what princeton word-net @xcite and others have imple-mented (e.g. turkish @xcite , bulgarian @xcite , romanian @xcite , czech @xcite , polish @xcite ). we consider derivational semantics resources relevant for nlp applications because the behavior of current large language model chat agents for less resourced languages like latvian shows a misunderstanding of meaning of derived words, so the application of lexical resources has value even in the era of large pre-trained models. latvian wordnet has been developed manually for the past four years @xcite . as of autumn 2024, latvian wordnet contains 8756 synsets which cover the meanings of the 2000 most frequently used words in the balanced corpus of modern latvian (levāne-petrova and dar ' gis, 2018) and their related synsets. the inventory of words and senses is based on the tēzaurs.lv online dictionary @xcite , which is a large (approximately 405000 entries in the last release in september 2024) digital compilation of legacy dictionaries. latvian wordnet is developed and maintained on the tēzaurs.lv lexicographic platform, and the data are available in dictionary entries of words whose senses are included in wordnet. this lexical resource also contains links between latvian wordnet and princeton wordnet @xcite . the important thing is that the latvian wordnet is created between separate word senses, and we also want to create the semantics of derivatives separately for each word sense, so we think these resources will be well integrated. currently, the semantics of derivatives is a network parallel to latvian wordnet, the word sense inventory being the unifying element which is involved in both networks. in the future, that will help to integrate one resource into the other. up until now, according to the traditions of lexicography, the regular derivatives listed in the tēzaurs.lv dictionary had their own entries only if they had a specific sense which was far removed from the senses of the base word. in order to represent the diversity of derivational relations, we are currently creating new entries for the most frequently used regular derivatives. in latvian linguistics little or no attention has been paid to semantic relations between the senses of a polysemous base word and the senses of its derivatives, as only general semantics of derivational formatives has been studied and described referring to the basic sense of the base word @xcite . in order to improve tēzaurs.lv and latvian wordnet, it should be verified whether these relations exist between all senses of the base word and the derivative (in more detail in chapter 3.3). therefore, we have chosen to employ two kinds of derivational links: morphological derivation links between lexemes and semantic derivation links between exact word senses (described in more detail in chapters 2 and 3). a morphological derivation link contains information about the formatives used in word formation, while a semantic link is formed as a pair of semantic labels that describe both linked senses. the choice of word pairs for annotating is determined by their frequency of use in the balanced corpus of modern latvian (levāne-petrova and dar ' gis, 2018). first, the derivatives of the most frequently used verbs, which are already included in latvian wordnet, are marked to enrich the lexical information of these words as much as possible. second, the most frequently used derivations in each derivation group are selected, for example, the most frequently used adjectives derived from nouns. the following word pairs are annotated in this phase of the project: a) verbs -deverbal nouns, b) nouns -denominal verbs, c) nouns -denominal adjectives, d) adjectivesdeadjectival adverbs. such groups were chosen to cover the four main word classes of the latvian language involved in word formation processes. other patterns of derivational links will be annotated as the project progresses, including patterns when a derivative is of the same word class as the base word. the processed data set currently includes 1000 morphological links and 1600 semantic links. to ensure a reliable resource for future research, the dataset is developed manually. however, we assume that in future some semi-automatic meth-ods could also be applied to unambiguous words to ensure a larger coverage, which is essential for nlp applications of this dataset. ## morphological derivational links a morphological derivation link between lexemes connects the base word entry to the derived word entry. this link contains two attributes: a derivational stem base and a derivational formative. the stem indicates which part and form of the base word the derivative is formed from. the formative is the means by which a new word is made; it can be a single morpheme, such as a prefix or a suffix, or a combination of morphemes, such as a suffix and an ending, that together form a complex formative. for example, the noun skrējējs 'runner' is formed by adding formatives -ēj-and -s to the past tense stem of the verb skriet 'to run'; and the adjective mākon ¸ains 'cloudy' is formed by adding formatives -ain-and -s to the plural stem of the noun mākonis 'cloud'. since the latvian language has an extremely rich inflectional and derivational morphology @xcite , new words can be made from various stems, e.g., the present, past, infinitive or participle stems of verbs and singular or plural stems of nouns, using prefixes, suffixes, endings, and interfixes. therefore, information about the derivational stem seems to be crucial in describing latvian derivational morphology. in addition, this information will help in further studies regarding the semantic properties that derivatives obtain with certain derivative formatives. although latvian grammars (e.g., @xcite ) provide general information of the semantic aspects of such formatives, wider language material could potentially lead to new insights, assist in determining previously undescribed peculiarities of derivative senses, and specify derivational stem bases. however, our aim does not include dividing the entire word into morphemes; the internal composition of latvian words is the objective of another project, "database of latvian morphemes and derivational models" (see https://www. dlmdm.lu.lv ). instead, we only indicate the morphemes involved in the derivative process. in most cases, the derivational direction between two words is clear, i.e., the base word and the derivative can be discerned by consulting the already described models of word formation. however, there are derivational relations in which it is not obvious which of the two is the base word and which is the derivative (e. g., kontrolēt 'to control' -kontrole 'control'; spēlēt 'to play (a game)' -spēle 'a game'). this problem arises mainly (but not exclusively) in pairs of loan words where it is not possible to establish which of the words was introduced into latvian first; this means that both derivational paths are possible in such cases, as both models of word formation are possible in latvian. a noun can be derived from a verb (e.g., atsaukties 'to refer' -atsauce 'a reference'; aizstāvēt 'to defend' -aizstāvis 'a defender'), and a verb can be derived from a noun (e.g., skaips 'skype' -skaipot 'to communicate via skype', balva 'an award'apbalvot 'to reward'). there are also more recent loan word pairs that are clearly derivationally linked, but are probably not derived from each other (e.g., biolo ' gija 'biology' -biolo ' gisks 'biological'; demokrātija 'democracy' -demokrātisks 'democratic'). in such instances, the solution is to label the link between lexemes as 'derivationally related' without specifying which is the base word and which is the derivative; information on the stem base and the formatives is also not provided. ## semantic derivational links due to the fact that semantic relations between the senses of a polysemous base word and the senses of its derivatives are yet to be studied in depth in latvian linguistics, a new system for annotating such instances had to be devised. this chapter describes the process of preparing entries for linking, creating semantic derivation links between the senses of the base word and its derivatives, semantic labels for each word class combination and more detailed observations of the relations between the senses of polysemous words. ## conclusions and future work the creation of derivational semantics resource has been started, the first such open-access resource for the latvian language. to reflect the possible difference in derivational semantics between the senses of one polysemous word, two types of links are created in the resource -a morphological link between lexemes and a semantic link between word meanings. a semantic link is formed by a pair of labels assigned to each linked sense. this results in a more informative resource than the general models of derivational semantics described in grammar alone. the first processed data consist of approx. 1000 morphological links and 1600 semantic links and the data is available in the autumn release of tēzaurs.lv, and from the winter release, it will also be available in the public version of tēzaurs.lv in the entries of the processed words. in the future, first of all, it is planned to cover other pairs of word classes involved in latvian derivation, including derivation pairs within the same word class. secondly, it is planned to automate part of the process -to find the existing entries of derivatives in the dictionary according to templates, to check in the corpus what kind of derivatives are used for a certain base word and compare with the dictionary data to create the missing entries. thirdly, it is planned to create a good search system in the data, so that we can further study which derivatives form which semantics. we would like to pay special attention to the semantic relations of polysemous words with their derivatives. plans for further work also include the integration of the derivational links within latvian wordnet, as there is a difference between synsetto-synset wordnet links and the derivational links that apply to specific words within that synset, and more study is needed to determine the proper representation for that interaction.