Universal Dependencies v2: An Evergrowing Multilingual Treebank Collection

Proceedings of the 12th Conference on Language Resources and Evaluation (LREC 2020), pages 4034–4043 Marseille, 11–16 May 2020 c⃝ European Language Resources Association (ELRA), licensed under CC-BY-NC 4034 Universal Dependencies v2: An Evergrowing Multilingual Treebank Collection Joakim Nivre∗ Marie-Catherine de Marneffe◦ Filip Ginter• Jan Hajiˇc† Christopher D. Manning‡ Sampo Pyysalo• Sebastian Schuster‡ Francis Tyers⋄ Daniel Zeman† ∗Uppsala University ◦The Ohio State University •University of Turku †Charles University in Prague ‡Stanford University ⋄Indiana University ∗joakim.nivre@lingfil.uu.se ◦demarneffe.1@osu.edu •{figint,sampo.pyysalo}@utu.fi †{hajic,zeman}@ufal.mff.cuni.cz ‡{manning,sebschu}@stanford.edu ⋄ftyers@iu.edu Abstract Universal Dependencies is an open community effort to create cross-linguistically consistent treebank annotation for many languages within a dependency-based lexicalist framework. The annotation consists in a linguistically motivated word segmentation; a morpholog- ical layer comprising lemmas, universal part-of-speech tags, and standardized morphological features; and a syntactic layer focusing on syntactic relations between predicates, arguments and modifiers. In this paper, we describe version 2 of the guidelines (UD v2), discuss the major changes from UD v1 to UD v2, and give an overview of the currently available treebanks for 90 languages. Keywords: treebanks, annotation, multilingual, universal dependencies. 1. Introduction Universal Dependencies (UD) is a project that is develop- ing cross-linguistically consistent treebank annotation for many languages, with the goal of facilitating multilingual parser development and research on parsing and cross- lingual learning. The annotation scheme is based on an evo- lution of (universal) Stanford dependencies (de Marneffe et al., 2006; de Marneffe and Manning, 2008; de Marneffe et al., 2014), Google universal part-of-speech tags (Petrov et al., 2012), and the Interset interlingua for morphosyn- tactic tagsets (Zeman, 2008). The general philosophy is to provide a universal inventory of categories and guidelines to facilitate consistent annotation of similar constructions across languages, while allowing language-specific exten- sions when necessary. The project started in 2014 and has developed into an open community effort with a very rapid growth, both in terms of the number of researchers contributing to the project, which now exceeds 300, and in terms of the number of languages represented by treebanks, which is approaching 100. An early snapshot of this development can be found in Nivre et al. (2016), which describes version 1 of the UD guidelines (UD v1) and the treebank resources available in UD v1.2. Since then, there has been one major change of the guide- lines, from UD v1 to UD v2, and the number of treebanks has more than quadrupled. Figure 1 shows the growth in number of languages, treebanks and annotated words from UD v1.0 to UD v2.5. During the same period, the num- ber of downloads or accesses at the official repository at https://lindat.cz has grown to 46439.1 The UD resources have also made a significant impact on NLP re- search, most notably for multilingual dependency parsing through two editions of CoNLL shared tasks (Zeman et al., 2017; Zeman et al., 2018), which have created a new gen- 1November 25, 2019. eration of parsers that handle a large number of languages and that parse from raw text rather than relying on pre- tokenized input. …

Content truncated to 500 words