Richly annotated dialogue corpora are essential for new research directions in statistical learning approaches to dialogue management, context-sensitive interpretation, and context-sensitive speech recognition. In particular, large dialogue corpora annotated with contextual information and speech acts are urgently required. We explore how existing dialogue corpora (usually consisting of utterance transcriptions) can be automatically processed to yield new corpora where dialogue context and speech acts are accurately represented. We present a conceptual and computational framework for generating such corpora. As an example, we present and evaluate an automatic annotation system which builds ‘Information State Update’ (ISU) representations of dialogue context for the Communicator (2000 and 2001) corpora of human–machine dialogues (2,331 dialogues). The purposes of this annotation are to generate corpora for reinforcement learning of dialogue policies, for building user simulations, for evaluating different dialogue strategies against a baseline, and for training models for context-dependent interpretation and speech recognition. The automatic annotation system parses system and user utterances into speech acts and builds up sequences of dialogue context representations using an ISU dialogue manager. We present the architecture of the automatic annotation system and a detailed example to illustrate how the system components interact to produce the annotations. We also evaluate the annotations, with respect to the task completion metrics of the original corpus and in comparison to hand-annotated data and annotations produced by a baseline automatic system. The automatic annotations perform well and largely outperform the baseline automatic annotations in all measures. The resulting annotated corpus has been used to train high-quality user simulations and to learn successful dialogue strategies. The final corpus will be made publicly available.

We describe a system that automatically learns effective and engaging dialogue strategies, generated from a library of dialogue content, using reinforcement learning from user feedback. Besides the more usual clarification and verification components of dialogue, this library contains various social elements like greetings, apologies, small talk, relational questions and jokes. We tested the method through an experimental dialogue system that encourages take-up of exercise and shows that the learned dialogue policy performs as well as one built by human experts for this system.

This article studies the issue of argument realization by preposition structures. By examining the preposition structures that are marked as frame elements in FrameNet, the article attempts to give corpus-based attestations to the hypothesized link between deep semantic arguments and their surface syntactic representations. Problems addressed in this article include how argument realization by preposition structures can be predictable from the target lexical unit and the frame it evokes, and why some noncentral prepositions get selected in the argument realization options. The investigation is primarily inspired by Fillmore's work in frame semantics. The source data for this study is derived from a preposition knowledge base that we have recently built by extracting all the semantically annotated preposition structures in FrameNet. The analysis shows that while there are various semantic–syntactic mapping possibilities, for most semantic arguments, the tendency of using central prepositions in their realization expressions is very strong. This is a clear indication that some preposition structures are linked to certain semantic arguments more than they are to others. A similar experiment was conducted using the annotated PropBank corpus to corroborate the supporting evidence found in FrameNet. The results of this study, together with the syntactic–semantic mapping lists of preposition structures can provide raw linguistic data for the study of preposition semantics, lexicography, argument realization, word sense disambiguation, and natural language understanding.

The FrameNet database comprises an English lexicon, organized in terms of semantic frames. Frames describe situations or entities, along with their participants and props, termed frame elements. The frames are organized in an ontology-like network. For the lexical units, corpus annotations illustrate which frame elements are typically realized, and how they behave syntactically. Texts where all content words are annotated with FrameNet information offer a detailed, structured semantic representation with a variety of uses in Natural Language Processing applications, in particular in retrieving and meaningfully organizing texts written by humans, or in making human–computer interaction more natural. Also, the FrameNet English lexicon can be replaced by lexical data from other languages, while maintaining frame information, so the model is attractive for cross-lingual resources and applications. Manual annotation produced by FrameNet and similar projects for other languages is used to train automatic frame semantic annotation systems, which add rich semantic information to any type of text, and are important components for more sophisticated semantic processing applications.