Design strategies for spoken language dialog systems

The development of task-oriented spoken language dialog system requires expertise in multiple domains including speech recognition, natural spoken language understanding and generation, dialog management and speech synthesis. The dialog manager is the core of a spoken language dialog system, and makes use of multiple knowledge sources. In this contribution we report on our methodology for developing and testing different strategies for dialog management, drawing upon our experience with several travel information tasks. In the LIMSI ARISE system for train travel information we have implemented a 2-level mixedinitiative dialog strategy, where the user has maximum freedom when all is going well, and the system takes the initiative if problems are detected. The revised dialog strategy and error recovery mechanisms have resulted in a 5-10% increase in dialog success depending upon the word error rate.