CROATPAS: A Resource of Corpus-derived Typed Predicate Argument Structures for Croatian
Authors: Costanza Marini, Elisabetta Jezek (Università di Pavia, 2019)
Topic: Lexical and Semantic Resources and Analysis

Abstract
The goal of this paper is to introduce CROATPAS, the Croatian sister project of the Italian Typed-Predicate Argument Structure resource (TPAS1, AUTHOR). CROATPAS is a corpus-based digital collection of verb valency structures with the addition of semantic type specifications (SemTypes) to each argument slot, which is currently being developed at the University of Pavia. Salient verbal patterns are discovered following a lexicographical methodology called Corpus Pattern Analysis (CPA,AUTHOR; AUTHOR; AUTHOR), whereas SemTypes – such as [HUMAN], [ENTITY] or [ANIMAL] – are taken from a shallow ontology shared by both TPAS and the Pattern Dictionary of English Verbs (PDEV2, AUTHOR; AUTHOR). The theoretical framework the resource relies on is Pustejovsky’s Generative Lexicon theory (AUTHOR), in light of which verbal polysemy and metonymic argument shifts can be traced back to compositional operations involving the variation of the SemTypes associated to the valency structure of each verb. The corpus used to identify verb patterns in CROATPAS is the Croatian Web as Corpus (hrWac 2.2, RELDI PoS-tagged) AUTHOR, which contains 1.2 billion types and is available on the Sketch Engine AUTHOR. The potential uses and purposes of the resource range from multilingual pattern linking between compatible resources to computer-assisted language learning (CALL).

Introduction
Nowadays, we live in a time when digital tools and resources for language technology are constantly mushrooming all around the world. However, we should remind ourselves that some languages need our attention more than others if they are not to face – to put it in Rehm and Hegelesevere’s words – “a steadily increasing and rather severe threat of digital extinction” AUTHOR. According to the findings of initiatives such as the META-NET White Paper Series (AUTHOR; AUTHOR), we can state that Croatian is unfortunately among the 21 out of 24 official languages of the European Union that are currently considered under-resourced. As a matter of fact, Croatian “tools and resources for […] deep parsing, machine translation, text semantics, discourse processing, language generation, dialogue management simply do not exist” (AUTHOR). An observation that is only strengthened by the update study carried out by AUTHOR, which shows that, in comparison with other European languages, Croatian has weak to no support as far as text analytics technologies go and only fragmentary support when talking of resources such as corpora, lexical resources and grammars. In this framework, a semantic resource such as CROATPAS could play its part not only in NLP, (e.g. multilingual pattern linking between other existing compatible resources), but also in automatic machine translation, computer-assisted language learning (CALL) and theoretical and applied cross-linguistic studies. The paper is structured as follows: first a detailed overview of the resource is presented (Section 2), followed by its theoretical underpinnings (Section 3) and a summary of the Croatianspecific challenges we faced while building the resource editor (Section 4). An overview of the existing related works is given in Section 5. Finally, Section 6 hints at the creation of a multilingual resource linking CROATPAS, TPAS (Italian) and PDEV (English) patterns and explores CROATPAS’s potential for computerassisted L2 teaching and learning.

Conclusion
In this paper, we introduced CROATPAS, a corpus-based digital collection of verb valency structures with the addition of semantic type specifications (SemTypes) to each argument slot. The resource relies on Pustejovsky’s Generative Lexicon theory (AUTHOR; AUTHOR) (Section 3) and is made up of four key-components, namely: 1) a representative corpus of contemporary Croatian (hrWac 2.2. RELDI PoS-tagged); 2) a shallow ontology of SemTypes; 3) a methodology for Corpus Pattern Analysis (CPA, AUTHOR); and 4) the adequate corpus tools (Sketch Engine). We discussed the Croatian-specific challenges we faced while building the editor in Section 4, and provided an overview of the existing related works in Section 5. In Section 6, we anticipated the future multilingual linking of verb patterns from CROATPAS, TPAS and PDEV, which could provide a resource to be exploited in NLP, automatic translation and both theoretical and applied cross-linguistic studies. Moreover, CROATPAS could become an interesting tool for computer-assisted language learning (CALL).