Verbal morphosyntactic disambiguation through topological field recognition in German-language law texts

Abstract

The morphosyntactic disambiguation of verbs is a crucial pre-processing step for the syntactic analysis of morphologically rich languages like German and domains with complex clause structures like law texts. This paper explores how much linguistically motivated rules can contribute to the task. It introduces an incremental system of verbal morphosyntactic disambiguation that exploits the concept of topological fields. The system presented is capable of reducing the rate of POS-tagging mistakes from 10.2% to 1.6%. The evaluation shows that this reduction is mostly gained through checking the compatibility of morphosyntactic features within the long-distance syntactic relationships of discontinuous verbal elements. Furthermore, the present study shows that in law texts, the average distance between the left and right bracket of clauses is relatively large (9.5 tokens), and that in this domain, a wide context window is therefore necessary for the morphosyntactic disambiguation of verbs.