Annotation and extraction of multiword expressions in Turkish treebanks

Abstract

Multiword expressions (MWEs) present particular and distinctive semantic properties, hence their automatic extraction receives special attention from the natural language processing (NLP) and corpus linguistics community, and is still an active research area. Unfortunately, the creation of necessary resources for this task is quite rigorous and many languages suffer from the lack of these; as in the case for Turkish. This study presents our MWE annotations on recently introduced Turkish Treebanks, which focuses on annotating various types of linguistic units and expressions, including named entities, numerical expressions, idiomatic phrases, verb phrases with auxiliaries and duplications. The paper aims to provide a benchmark and pave the way towards further MWE extraction research for Turkish. To this end, the paper also introduces our experimental results with seven baseline approaches, a dependency parser and a previously introduced rule-based extractor on these annotated corpora. Our highest performances achieved over these resources are about 60% F-scores.