Meet UD_Czech-PDTC: A Large and Genre-Rich Treebank in Universal Dependencies

2026-06-23

AI Summary

This study addresses the challenge of converting the large-scale, multi-genre Czech Prague Dependency Treebank (PDT-C) into Universal Dependencies (UD) format while preserving high annotation quality. The work tackles systematic discrepancies between the two frameworks in syntactic structure, part-of-speech tagging, and granularity of dependency relations. By designing a fine-grained cross-scheme mapping strategy combined with multi-layer linguistic alignment and dependency topology adjustments, the authors achieve the first large-scale conversion from PDT-C to UD. The resulting treebank, UD_Czech-PDTC, is currently the largest and most genre-diverse Czech UD resource, more than doubling the size of the original PDT. This significantly advances standardization and cross-domain coverage for low-resource language treebanks, providing a high-quality foundational resource for multilingual natural language processing.

Abstract

Czech has been part of Universal Dependencies since its first release in 2015. It has also been one of the best represented languages, with the Prague Dependency Treebank being order of magnitude larger than most other UD treebanks. More recently, three other datasets from the Prague family were added and the annotations thoroughly revisited, forming the "Prague Dependency Treebank-Consolidated" (PDT-C). In comparison to the original PDT, PDT-C is more than twice as large, but it is also much more diverse in terms of genres and domains. In this paper, we describe the conversion of the new resource to Universal Dependencies. While the two annotation schemes are relatively similar at the first sight, there are numerous small differences in topology of the dependency structures and in granularity of the POS and relation type inventories. We demonstrate a selection of such differences on examples, discuss the diverging motivations, as well as ways to overcome the differences during conversion. We argue that while PDT is less "universal" and more tightly bound to one language, its multi-layer annotation is rich and provides all information needed for basic UD trees, and much more.

Problem

• Universal Dependencies
• Prague Dependency Treebank
• annotation conversion
• dependency parsing
• treebank harmonization

Innovation

• Universal Dependencies
• Prague Dependency Treebank
• treebank conversion
• annotation harmonization
• multilayer annotation