Abstract
This paper investigates the development of a natural language (NL) interface for mixed initiative dialogues within a constrained domain and demonstrates the applicability of the functional approach to NL system development. The system consists of two major components, a natural language subsystem comprises a general-purpose parser that interprets a ‘plug and play’ tagged BNF grammar (which may be ambiguous), to parse natural language input and extract semantic information. The knowledge-based subsystem uses the semantic tags extracted by the natural language subsystem to generate a focused query to select the most appropriate script for a guided dialogue with the user. The system was written entirely in a purely functional language, which resulted in a surprisingly small and simple program.
