Analyse syntaxique à l'aide des tables du Lexique ... - Accueil

Abstract
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 largecoverage
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 parsers Passage (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.
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