On-line Interpretation in Speech Understanding and Dialogue Systems (original) (raw)

1988, Recent Advances in Speech Understanding and Dialog Systems

This paper addresses syntactic, semantic and pragmatic aspects of central concern in the design of on-line language understanding systems. In the area of syntax, the paper focuses on the phenomenon of discontinuous constituents. A form of syntactic representation is defined, called discontinuous trees, which allows the constituent structure of sentences with discontinuous constituents to be represented without changing the word order in the sentence. A kind of phrase-structure gram.mar is defined which can generate such representations, and an on-line parsing algorithm is presented which parses sentences into these representations. In the area of semantics, the paper focuses on the effective resolution of ambiguity and vagueness, and on the on-line interpretation of anaphora. For dealing with ambiguous and vague expressions in an effective, on-line manner a cascaded model-theoretic approach is developed which makes use of intermediate semantic representations in a formal language that preserves some of the ambiguity and vagueness in natural language. For the interpretation of anaphora, an approach is outlined that has recently been suggested by Groenendijk and Stokhof, based on the use of dynamic logic. In the area of pragmatics, the paper focuses on the analysis of informationexchange dialogues as consisting of communicative actions. The notion function of a communicative action is defined in terms of the flow of information between speaker and addressee. It is argued that Groenendijk and Stokhof's dynamic approach to semantic interpretation can be elegantly combined with this`functional' approach to communicative action into in an integrated theory of utterance meaning. The resulting`dyna~nic interpretation theory' is outlined, which offers exciting perspectives for a full-fledged, on-line utterance interpretation process. (1) A process F is on-line if there is a function f such that for every input sequence C il, iz, .., ik~: F(G ii~iz,.-~ik~)-f(F(C ai~iz~..~tk-l1~Zk) Note that, if C il, iz, .., ik 1 is a sequence of inputs which forms part of a complete input sequence G il, izi .., i"~, according to this definition the processing of that part indeed takes place immediately, as it does not depend on later inputs.