Current Research in Natural Language Generation

Abstract

Current Research in Natural Language Generation is derived from the Second European Natural Language Generation Workshop, which was held in Edinburgh in April 1989. The papers included in this volume were selected from revised versions of some of the papers presented at the workshop. The book provides a snapshot of the current research in NLG, with particular emphasis on the work conducted by the European research community. It is aimed at an audience already familiar with NLG. Even though the different papers provide introductory technical material where necessary, in general, this material alone seemed insufficient to enable the uninitiated to understand completely the different arguments. However, adequate references are provided. The book is divided into four main sections: text planning (four papers), linguistic realization (two papers), building descriptions (three papers), and connectionist approaches (two papers). The first section contains contributions by Hovy, Scott and de Souza, Cawsey, and McKeown et al. The first paper, entitled Unresolved issues in paragraph by Hovy, is a position paper that raises seven unresolved problems in discourse planning, mainly from the perspective of Rhetorical Structure Theory (RST) (Mann and Thompson 1988). These problems are divided into two groups: problems concerning the theory and representation of coherence relations, and algorithmic problems. The importance of this paper is that it focuses the discussion on NLG on crucial issues to which researchers have to address themselves. The second paper, Getting the message across in RST-based generation, by Scott and de Souza, addresses the problem of generating text that achieves a communicative goal effectively. To this end, the authors look upon style in terms of a reader's ease of processing a text, rather than in terms of aesthetics. The main contribution of the paper is that it presents explicit heuristics grounded in psycholinguistic evidence to control the realization of RST discourse relations. I found Section 3.2, Making the text sensitive to the communicative setting, where the authors link the generation of textual markers to context sensitivity, somewhat problematic. In addition, since the heuristics presented in the paper were not implemented, some analysis of how they interact would have been useful. The third paper, Generating explanatory discourse, by Cawsey, discusses an interactive content and discourse planner whose output is tailored to the changing capabilities of the user, and which can also handle interruptions and remedial discourse. The paper offers a novel approach that addresses specific criteria in discourse planning. Its contributions include: the use of an approach similar to Litman's (1985) to separate content and discourse planning; the hierarchical decomposition of schemata; and the use of an agenda for content planning. This paper provides a clear exposition