SYMPAThy: Towards a comprehensive approach to the extraction of Italian Word Combinations
Authors: Alessandro Lenci, Gianluca E. Lebani, Sara Castagnoli, Francesca Masini, Malvina Nissim (Università di Pisa, Università di Bologna, 2014)
Topic: Lexical and Semantic Resources and Analysis

Abstract
The paper presents SYMPAThy, a new approach to the extraction of Word Combinations. The approach is new in that it combines pattern-based (P-based) and syntax-based (S-based) methods in or-der to obtain an integrated and unified view of a lexeme’s combinatory potential.

Introduction
The term Word Combinations (WOCs), as used here, broadly refers to the range of combinatory possibilities typically associated with a word. On the one hand, it comprises so-called Multi-word Expressions (MWEs), intended as a variety of recurrent word combinations that act as a single unit at some level of linguistic analysis (Calzolari et al., 2002; Sag et al., 2002; Gries, 2008): they include phrasal lexemes, idioms, collocations, etc. On the other hand, WOCs also include the preferred distributional interactions of a word (be it a verb, a noun or an adjective) with other lexical entries at a more abstract level, namely that of argument structure patterns, subcategorization frames, and selectional preferences. Therefore, WOCs include both the normal combinations of a word and their idiosyncratic exploitations (Hanks, 2013). The full combinatory potential of a lexical entry can therefore be defined and observed at the level of syntactic dependencies and at the more constrained surface level. In both theory and practice, though, these two levels are often kept separate. Theoretically, argument structure is often perceived as a “regular” syntactic affair, whereas MWEs are characterised by “surprising properties not predicted by their component words” (Baldwin and Kim, 2010, 267). At the pratical level, in order to detect potentially different aspects of the combinatorics of a lexeme, different extraction methods are used – i.e. either a surface, patternbased (P-based) method or a deeper, syntax-based (S-based) method – as their performance varies according to the different types of WOCs/MWEs (Sag et al., 2002; Evert and Krenn, 2005). We argue that, in order to obtain a comprehensive picture of the combinatorial potential of a word and enhance extracting efficacy for WOCs, the P-based and S-based approaches should be combined. Thus, we extracted corpus data into a database where both P-based and S-based information is stored together and accessible at the same time. In this contribution we show its advantages. This methodology has been developed on Italian data, within the CombiNet1 project, aimed at building an online resource for Italian WOCs.

Conclusion
In this paper we presented SYMPAThy, a new method for the extraction of WOCs that exploits a variety of information typical of both P-based and S-based approaches. Although SYMPAThy was developed on Italian data, it can be adapted to other languages. In the future, we intend to exploit this combinatory base to model the gradient of schematicity/productivity and fixedness of combinations, in order to develop an “WOC-hood” indicator to classify the different types of WOCs on the basis of their distributional behavior.