Developing a U niversal D ependencies Treebank for U krainian Parliamentary Speech (2025)

Abstract: This paper presents a new Universal Dependencies (UD) treebank based on Ukrainian parliamentary transcripts, complementing the existing UD resources for Ukrainian. The corpus includes manually annotated texts from key historical sessions of the Verkhovna Rada, capturing not only official rhetoric but also features of colloquial spoken language. The annotation combines UDPipe2 and TagText parsers, with subsequent manual correction to ensure syntactic and morphological accuracy. A detailed comparison of tagsets and the disambiguation strategy employed by TagText is provided. To demonstrate the applicability of the resource, the study examines vocative and nominative case variation in direct address using a large-scale UD-annotated corpus of parliamentary texts.

## introduction universal dependencies (ud) is a framework that aims to create a consistent, multilingual annotation scheme for syntactic structures across languages @xcite , and it has become an important tool for ukrainian language processing. on the one hand, it enables deeper integration into international multilingual projects that rely on a unified annotation scheme across languages. on the other hand, it provides a valuable resource for studying the ukrainian language itself, as ud currently offers the only publicly available system for syntactic annotation of ukrainian texts. ud annotation has already been used in multilingual projects involving ukrainian, such as the parlamint parliamentary transcript corpora @xcite ) @xcite , and the parallel corpora collections, namely intercorp @xcite and pararook @xcite . as the list of such multilingual projects tends to expand @xcite , the importance of having universal tools like ud becomes even more critical. this ensures that ukrainian data is compatible with existing and future multilingual projects, allowing us to actively participate in their development. ## ud treebanks for ukrainian currently, there are two ud treebanks for ukrainians. the first is ukrainian iu foot_0 by natalia @xcite @xcite . the treebank consists of 122,000 tokens in 7,000 sentences drawn from various sources, including fiction, news, opinion articles, wikipedia, legal documents, letters, posts, and comments. the texts span the last 15 years and the first half of the 20th century, offering a diverse corpus of ukrainian written speech. the second is ukrainian parlamint treebank of 52,000 tokens in 3,400 sentences, which was published in the ud repository in 2024 and is a corpus of ukrainian parliamentary transcripts. 2 the transcripts published on the official website of verkhovna rada provide a fairly accurate record of real speech, preserving elements of colloquial syntax, grammatical inconsistencies, lexical errors, and ukrainian-russian code switching @xcite . as such, they serve as valuable material for studying spoken ukrainian and complement the corpora of written texts. for example, although the ukrainian iu treebank is larger in volume, it includes only about a hundred instances of direct address, whereas ukrainian parlamint treebank features more than 500. the udpipe2 model foot_2 @xcite trained on ud_ukrainian-parlamint makes fewer errors in detecting vocative dependency relations, in particular in less regular positions of direct address in the middle and at the end of the sentence (90% precision for the vocative dependency relation; see appendix a). thus, the treebank of parliamentary transcripts complements the existing treebank of written texts by providing grammatical patterns that are more typical of spoken language and less frequent in written sources. ## vocative vs. nominative in direct address: study on a large corpus annotated with udpipe2 although the modern norm of the ukrainian language recommends using only the vocative case in addresses @xcite , in practice there is a variation between the vocative and nominative cases. the study of this variation in a corpus with only morphological annotation, without syntactic one, like grac foot_11 , is practically impossible due to the difficulty of distinguishing between the different syntactic functions of the nominative case (address, subject, predicate, appositional modifier, list element) and homonymy with the accusative case forms. the ud annotation makes it possible to analyze the use of vocative and nominative cases within the vocative dependency relation, and thus to assess trends in a large textual material. using the udpipe2 ukrainian-parlamint-ud-2.15-241121 model, we annotated the corpus of ukrainian parliament transcripts from 1990 to 2024, totaling 88 million tokens foot_12 , from which we obtained more than 128 thousand contexts with the vocative relation. the precision of the data was manually verified. we included only singular masculine and feminine nouns, except for indeclinable nouns (e.g., pani 'madam', jerry, geo), and nouns that decline according to the adjectival paradigm (e.g., včenyj 'scholar'). we also excluded examples consisting of a single surname, as the model often fails to distinguish between masculine and homonymous feminine surnames that do not decline. the corpus shows significant variation between vocative and nominative in addresses, except for the data before 1995 and for 1997-2001, which show 100% use of the vocative and were likely edited. the proportion of nominative or vocative varies considerably for different lemmas, thus the material requires a deeper linguistic study to find the reasons for the variation (appendix c). the resource appears to be highly promising both for corpus-based studies of ukrainian grammar, in particular, the grammar of spoken language, and for providing annotation of ukrainian corpora. in future work, we plan to expand the size of the corpus and explore new annotation possibilities within the ud framework. one such direction is the annotation of extpos (external part of speech), which has already been added to the ukrainian parlamint corpus in its second release, completed shortly after the main work on this paper foot_13 . we also plan to explore the possibility of annotating morphosyntactic features of multiword expressions, so that analytical grammatical forms in ukrainian, such as the conditional mood or the analytical future, can be represented as annotation features. this would significantly enhance the resource's potential for advanced grammatical research and facilitate more fine-grained linguistic analysis.