An English-Italian MWE dictionary
Authors: Johanna Monti (Università degli Studi di Sassari, 2014)
Topic: Lexical and Semantic Resources and Analysis

Abstract
The translation of Multiword Ex-pressions (MWEs) requires the knowledge of the correct equivalent in the target language which is hardly ever the result of a literal translation. This paper is based on the as-sumption that the proper treatment of MWEs in Natural Language Processing (NLP) appli-cations and in particular in Machine Transla-tion and Translation technologies calls for a computational approach which must be, at least partially, knowledge-based, and in par-ticular should be grounded on an explicit lin-guistic description of MWEs, both using an electronic dictionary and a set of rules. The hypothesis is that a linguistic approach can complement probabilistic methodologies to help identify and translate MWEs correctly since hand-crafted and linguistically-motivated resources, in the form of electronic dictionaries and local grammars, obtain accu-rate and reliable results for NLP purposes. The methodology adopted for this research work is based on (i) Nooj, an NLP environ-ment which allows the development and test-ing of the linguistic resources, (ii) an electron-ic English-Italian MWE dictionary, (iii) a set of local grammars. The dictionary mainly consists of English phrasal verbs, support verb constructions, idiomatic expressions and col-locations together with their translation in Ital-ian and contains different types of MWE POS patterns.

Introduction
This paper presents a bilingual dictionary of MWEs from English to Italian. MWEs are a complex linguistic phenomenon, ranging from lexical units with a relatively high degree of internal variability to expressions that are frozen or semi-frozen. They are very frequent and productive word groups both in everyday languages and in languages for special purposes and are the result of human creativity which is not ruled by algorithmic processes, but by very complex processes which are not fully representable in a machine code since they are driven by flexibility and intuition. Their interpretation and translation sometimes present unexpected obstacles mainly because of inherent ambiguities, structural and lexical asymmetries between languages and, finally, cultural differences. The identification, interpretation and translation of MWEs still represent open challenges, both from a theoretical and a practical point of view, in the field of Machine Translation and Translation technologies. Empirical approaches bring interesting complementary robustness-oriented solutions but taken alone, they can hardly cope with this complex linguistic phenomenon for various reasons. For instance, statistical approaches fail to identify and process non high-frequent MWEs in texts or, on the contrary, they are not able to recognise strings of words as single meaning units, even if they are very frequent. Furthermore, MWEs change continuously both in number and in internal structure with idiosyncratic morphological, syntactic, semantic, pragmatic and translational behaviours. The main assumption of this paper is that the proper treatment of MWEs in NLP applications calls for a computational approach which must be, at least partially, knowledge-based, and in particular should be grounded on an explicit linguistic description of MWEs, both using a dictionary and a set of rules. The methodology adopted for this research work is based on: (I) Nooj an NLP environment which allows the development and testing of the linguistic resources, (ii) an electronic English-Italian (EI) MWE dictionary, based on an accurate linguistic description that accounts for different types of MWEs and their semantic properties by means of well-defined steps: identification, interpretation, disambiguation and finally application, (iii) a set of local grammars.

Conclusion
In conclusion, the focus of this research for the coming years will be to improve the results ob-tained so far and to extend the research work to provide a more comprehensive methodology for MWE processing in MT and translation technol-ogies, taking into account not only the analysis phase but also the generation one. This experiment provides, on the one hand, an investigation of a broad variety of combinations of MWE types and an exemplification of their behaviour in texts extracted from different corpo-ra and, on the other hand, a representation method that foresees the interaction of an electronic dic-tionary and a set of local grammars to efficiently handle different types of MWEs and their proper-ties in MT as well as in other types of NLP appli-cations. This research work has therefore produced two main results in the field of MWE processing so far: the development of a first version of an English-Italian electronic dictionary, spe-cifically devoted to different MWEs types, the analysis of a first set of specific MWE structures from a semanto-syntactic point of view and the develop-ment of local grammars for the identifica-tion of continuous and discontinuous MWEs in the form of FST/FSA.