News & Events

Department of Chinese, Translation and Linguistics
Research Seminar

Non Sentential Utterances: Meaning, Content, and Complexity

Presented by

Prof. Jonathan Ginzburg

Department of Computer Science, King's College, London

Date: 10 July 2008, Thursday
Time: 4:30pm - 6:00pm
Venue: B7516 (Lift 3, 7/F, Blue Zone), Academic Building, CityU

Abstract

Non sentential utterances (NSUs), examples of which are in (1)-(4), are pervasive in conversation: (1) A: Did Bo leave? B: Yes / No, Jo/ Bo? (2) A: Did Bo ... B: leave? (3) A: Did Bo ... No, Jo leave? (4) A: [in a ticket office] A return to Maidenhead please. NSUs have had a rather mixed reputation in theoretical and computational linguistics. Beliefs about the intrinsic messiness of conversation, in particular its being littered with fragments, have been used as important motivation for a strong modularity assumption in language acquisition (starting with Chomsky 1965, 1972 but persisting to this day in textbooks). Conversely, computational linguists have argued that fragment resolution generally requires plan recognition techniques (e.g. Allen and Perrault, 1980; Carberry, 1991). The starting point for this talk will be recent work, jointly with Raquel Fernàndez and Shalom Lappin, showing that conversational NSUs are actually amenable to domain independent classification: a taxonomy of fewer than 20 classes reliably classifies the NSUs in the British National Corpus and the taxonomy can be learnt by a variety of machine learning algorithms. I will show that given a sufficiently detailed theory of conversational interaction (as exemplified by the theory sketched in my first talk), fragment resolution is relatively straightforward, akin in a sense to the resolution of traditional indexical elements. I will show how to associate a hierarchy of complexity among NSUs and discuss some predictions this makes about the order of acquisition of NSUs.

Speaker