  The two principal areas of natural language processing research in pragmatics
are belief modelling and speech act processing. Belief modelling is the
development of techniques to represent the mental attitudes of a dialogue
participant. The latter approach, speech act processing, based on speech act
theory, involves viewing dialogue in planning terms. Utterances in a dialogue
are modelled as steps in a plan where understanding an utterance involves
deriving the complete plan a speaker is attempting to achieve. However,
previous speech act based approaches have been limited by a reliance upon
relatively simplistic belief modelling techniques and their relationship to
planning and plan recognition. In particular, such techniques assume
precomputed nested belief structures. In this paper, we will present an
approach to speech act processing based on novel belief modelling techniques
where nested beliefs are propagated on demand.
