Analyse syntaxique à l'aide des tables du Lexique-Grammaire du français

摘要

Lexicon-Grammar tables, whose development was initiated by Gross (1975), are a very rich syntactic lexicon for the French language. They cover various lexical categories such as verbs, nouns, adjectives and adverbs. This linguistic database is nevertheless not directly usable by computer programs, as it is incomplete and lacks consistency. Tables are defined on the basis of features which are not explicitly recorded in the lexicon. These features are only described in literature. To use these tables, we must make explicit the essential features appearing in each one of them. In addition, many features must be renamed for consistency sake. Our aim is to adapt the tables, so as to make them usable in various Natural Language Processing (NLP) applications, in particular parsing.We describe the problems we encountered and the approaches we followed to enable their integration into a parser. We propose LGExtract, a generic tool for generating a syntactic lexicon for NLP from the Lexicon-Grammar tables. It relies on a global table in which we added the missing features and on a single extraction script including all operations related to each property to be performed for all tables. We also present LGLex, the new generated lexicon of French verbs, predicative nouns, frozen expressions and adverbs.Then, we describe how we converted the verbs and predicatives nouns of this lexicon into the Alexina framework, that is the one of the Lefff lexicon (Lexique des Formes Fléchies du Français) (Sagot, 2010), a freely available and large-coverage morphological and syntactic lexicon for French. This enables its integration in the FRMG parser (French MetaGrammar) (Thomasset et de La Clergerie, 2005), a large-coverage deep parser for French, based on Tree-Adjoining Grammars (TAG), that usually relies on the Lefff. This conversion step consists in extracting the syntactic information encoded in Lexicon-Grammar tables. We describe the linguistic basis of this conversion process, and the resulting lexicon. We evaluate the FRMG parser on the reference corpus of the evaluation campaign for French parsersPassage (Produire des Annotations Syntaxiques à Grande Échelle) (Hamon et al., 2008), by comparing its Lefff-based version to our version relying on the converted Lexicon-Grammar tables