This paper reports on development of a natural language processing system based on human communication theory. Our system, DIALS (for DIALogue Structures), implements and extends the theory of metacommunication developed in the field of human speech communication. The theory of Dialogue Structures is based on research showing that the interpretation of conversation is enabled by metacommunications helpful in managing interactions and that indirect requests are usually patterns expressing relationships in the interaction rather than simply expressing the content of the request. As such,indirect requests are best interpreted by a semantic grammar expert at managing communciation, rather than a semantic grammar knowledgable on some specific task domain. Our system, based on this approach,correctly interprets all indirect requests from a corpus of 1500 requests transcribed from tape recordings with a combined total of over 80minutes of continuous conversation of 27 dialogues between airline reservation agents and customers.

This paper reports a new theory of natural language processing and its implementation in a computerprogram, DIALS (for DIALogue Structures). This represents a radical departure from the paradigmaticapproach to natural language processing currently dominating the Helds of artificial intelligence, linguistics,and language philosophy, among others. W e use the theory of metacommunication to develop a"pragmatic grammar" for the structural analysis of dialogue. W e are currently able to parse and generateover 5000 surface forms of a single underlying request content. W e propose using this pragmatic informationto manage the communication context, including inferring some of a speakers' goals and controllingstatus and politeness.