Interpreting Cohesive Forms in the Context of Discourse Inference

Abstract

In this thesis, we present analyses and algorithms for resolving a variety of cohesive phenomena in natural language, including VP-ellipsis, gapping, event reference, tense, and pronominal reference. Past work has attempted to explain the complicated behavior of these expressions with theories that operate within a single module of language processing. We argue that such approaches cannot be maintained; in particular, the data we present strongly suggest that the nature of the coherence relation operative between clauses needs to be taken into account. We provide a theory of coherence relations and the discourse inference processes that underly their recognition. We utilize this theory to break the deadlock between syntactic and semantic approaches to resolving VP-ellipsis. We show that the data exhibits a pattern with respect to our categorization of coherence relations, and present an account which predicts this pattern. We extend our analysis to gapping and event reference, and show that our analyses result in a more independently-motivated and empirically-adequate distinction among types of anaphoric processes than past analyses. We also present an account of VP-ellipsis resolution that predicts the correct set of strict and sloppy readings for a number of benchmark examples that are problematic for past approaches. The correct readings can be seen to result from a general distinction between referring and copying in anaphoric processes. The account also extends to other types of reference, such as event reference and `one'-anaphora. Finally, we utilize our theory of coherence in analyses that break the deadlock between definite-reference and coherence-based approaches to tense and pronoun interpretation. We present a theory of tense interpretation that interacts with discourse inference processes to predict data that is problematic for both types of approach. We demonstrate that the data commonly cited in the pronoun interpretation literature also exhibits a pattern with respect to coherence relations, and make some preliminary proposals for how such a pattern might result from the properties of the different types of discourse inference we posit.