Parsing into Discourse Object Descriptions

This paper reports work on the design of a natural language interface with a limited dialogue capability. It is argued that (i) The interpretation of the input is preferably represented as a structure of Discourse Object Descriptions (DODs); (ii) The DODs must be determined on the basis of different types of knowledge such as grammatical knowledge, object type deirmitions and knowledge about existing discourse objects and their discourse status; (iii) The different types of knowledge are stored separately but integrated in the interpretation process which is based on constraints. I N T R O D U C T I O N The LINLIN-project is concerned with the development of general-purpose natural language interfaces (NLIs) to computer software with special emphasis on communication in Swedish. A useful general-purpose NLI must meet a var/ety of requirements, a number of which concern communicative ability. The communicative abilities of as NLI are necessarily restricted by the limitations of existing techniques, but can also be purposely restricted to enhance transparency. It is not certain that the linguistically more competent NLI is the most useful one, e.g. if its behaviour appears idiosyncratic to the user. In any case, the language of an NLI is a language des igned (and is in that respect not a natural language) so there are many questions to be answered about h o w it should be designed, both in terms of how it should function as a vehicle of communication and in terms of internal representations and procedures. As for the first aspect we are conducting a series of simulations to fred out what communicative abilities an NLI should have (Dahlb~k&J~neson, 1986), but meanwhile we are assuming that LINLIN should meet the following demands: it should have a fair knowledge of the structure of Swedish words, clauses and utterances, an