A too level modular system for natural language understanding

This paper is intended to propose a new methodological approach to the conception of natural lan guage understanding systems. This contribution is supported by the design and implementation of DONAU. The system is based on a two level modular architecture. The horizontal level allows an independent and parallel development of the single segments of the system (syntactic analyser, semantic analyser, information extractor, legality controller). The vertical level ensures the possibility of changing the definition of the semantic domain on which particular versions of the system can be oriented and specialized in a simple, incremental, and user-oriented way. DONAU is written in LISP and is available from the authors.