A Symbolic Approach to Near-Deterministic Surface Realisation using Tree Adjoining Grammar

International audienceSurface realisers divide into those used in generation (NLG geared realisers) and those mirroring the parsing process (Reversible realisers). While the first rely on grammars not easily usable for parsing, it is unclear how the second type of realisers could be parameterised to yield from among the set of possible paraphrases, the paraphrase appropriate to a given generation context. In this paper, we present a surface realiser which combines a reversible grammar (used for parsing and doing semantic construction) with a symbolic means of selecting paraphrases

Benchmarking for syntax-based sentential inference

International audienceWe propose a methodology for investigat- ing how well NLP systems handle mean- ing preserving syntactic variations. We start by presenting a method for the semi automated creation of a benchmark where entailment is mediated solely by meaning preserving syntactic variations. We then use this benchmark to compare a seman- tic role labeller and two grammar based RTE systems. We argue that the proposed methodology (i) supports a modular eval- uation of the ability of NLP systems to handle the syntax/semantic interface and (ii) permits focused error mining and er- ror analysis

A Serious Game for Second Language Acquisition in a Virtual Environment

International audienceIn this paper, we present I-FLEG, a 3D language game designed for interactively learning French as a second language. I-FLEG differs from previous computer-aided language learning (CALL) approaches in that it combines a situated, language learning environment with advanced artificial intelligence and natural language generation techniques which support user adaptivity and the automatic, context-aware generation of learning material. In addition, because it is integrated in a 3D virtual reality environment, I-FLEG naturally supports elearning and facilitates the collection of test data

XMG : eXtensible MetaGrammar

International audienceIn this article, we introduce eXtensible MetaGrammar (xmg), a framework for specifying tree-based grammars such as Feature-Based Lexicalised Tree-Adjoining Grammars (FB-LTAG) and Interaction Grammars (IG). We argue that xmg displays three features which facilitate both grammar writing and a fast prototyping of tree-based grammars. Firstly, \xmg\ is fully declarative. For instance, it permits a declarative treatment of diathesis that markedly departs from the procedural lexical rules often used to specify tree-based grammars. Secondly, the \xmg\ language has a high notational expressivity in that it supports multiple linguistic dimensions, inheritance and a sophisticated treatment of identifiers. Thirdly, xmg is extensible in that its computational architecture facilitates the extension to other linguistic formalisms. We explain how this architecture naturally supports the design of three linguistic formalisms namely, FB-LTAG, IG, and Multi-Component Tree-Adjoining Grammar (MC-TAG). We further show how it permits a straightforward integration of additional mechanisms such as linguistic and formal principles. To further illustrate the declarativity, notational expressivity and extensibility of \xmg , we describe the methodology used to specify an FB-LTAG for French augmented with a unification-based compositional semantics. This illustrates both how xmg facilitates the modelling of the tree fragment hierarchies required to specify tree-based grammars and of a syntax/semantics interface between semantic representations and syntactic trees. Finally, we briefly report on several grammars for French, English and German that were implemented using \xmg\ and compare \xmg\ to other existing grammar specification frameworks for tree-based grammars