| To decide how to respond to an utterance, a speaker must interpret what others have said and why they have said it. Speakers rely on their expectations to decide whether they have understood each other. Misunderstandings occur when speakers differ in their beliefs about what has been said or why. If a listener hears something that seems inconsistent, he may reinterpret an earlier utterance and respond to it anew. Otherwise, he assumes that the conversation is proceeding smoothly. Recognizing an inconsistency as a misunderstanding and generating a new reply together accomplish what is known as a fourth-position repair.; To model the repair of misunderstandings, this thesis combines both intentional and social accounts of discourse, unifying theories of speech act production, interpretation, and repair. In intentional accounts, speakers use their beliefs, goals, and expectations to decide what to say; when they interpret an utterance, speakers identify goals that might account for it. In sociological accounts provided by Ethnomethodology, discourse interactions and the resolution of misunderstandings are normal activities guided by social conventions. The approach extends intentional accounts by using expectations deriving from social conventions in order to guide interpretation. As a result, it avoids the unconstrained inference of goals that has plagued many models of discourse. A unified theory has been developed by using default reasoning to generate utterances and using abduction to characterize interpretation and repair.; The account has been expressed as a logical theory within the Prioritized Theorist Framework. The theory includes relations on linguistic acts and the Gricean attitudes that they express. It also contains an axiomatization of speakers' knowledge for generating socially appropriate utterances and for detecting and repairing misunderstandings. The generality of the approach is demonstrated by re-enacting real conversations using the theorem-proving capabilities of Prioritized Theorist. |
