Parsing in Dialogue Systems using Typed Feature Structures

The analysis of natural language in the context of keyboard-driven dialogue systems is the central issue addressed in this paper. A module that corrects typing errors and performs domain-specifc morphological analysis has been developed. A parser for typed unification grammars is designed and implemented in C++; for description of the lexicon and the grammer a specialised specification language has been developed. It is argued that typed unification grammars and especially the newly developed specification language are convenient formalisms for describing natural language use in dialogue systems. Research on these issues is carried out in the context of the Schisma project, a research project of the Parlevink group in linguistic engineering; participants in Schisma are KPN Research and the University of Twente. The aims of the Schisma project are twofold: both the accumulation of knowledge in the field of computational linguistics and the development of a natural language interfaced theatre information and booking system is envisaged. The Schisma project serves as a testbed for the development of the various language analysis modules necessary for dialogue systems

TOWARDS AN AUTOMATIC IDENTIFICATION OF TOPIC AND FOCUS

The purpose of the paper is (i) to substantiate the claim that the output of an automatic analysis should represent among other things also the hierarchy of toplc-focus articulation, and (ii) to present a general procedure for determin-ing the toplc-focus articulation in Czech and English. (i) The following requirements on the output of an automatic analysis are significant: (a) in the output of the analysis it should be marked which elements of the analyzed sentence belong to its topic and which to the focus$ (b) the scale of communicative dynamism (CD) should also be identified for every representation of a meaning of the-n-ly-zed sentence, since the degrees of CD correspond to the unmarked distribution of quantifier scopes in the semantic interpretation of the sentences (c) the analysis should also distinguish toplcless sentences from those hav~ng a topic, which is relevant for the scope of negation. (ii) For an automatic recognition of topic, focus and the degrees of CD, two ~ oints are crucial: a) either the input language has (a considerable degree of) the so-called free word order (as in Czech, Russian), or its word order is determined mainly by the grammatical relations (as in English, Prench); (b) either the input is spoken discourse (and the recognition procedure includes an acoustic analysis), or written (printed) texts are analyzed. In accordance with these points, a general procedure for determining topic, focus and the degrees of CD is formulated for Czech and English, with some hints how the preceding context can be taken into account

On the Notion of Topic

this paper is to discuss the notion of what we call the topic of a sentence