Automated Appointment Scheduling

We describe a spoken language system that schedules appointments over the telephone. The system has a calendar of available times for some service that callers want to obtain. The system and the caller engage in a cooperative dialogue until a mutually satisfactory appointment time can be found and scheduled. The system has three parts: a speech recog-nizer based on neural network phoneme classiication and word bigrams, a robust phrase-spotting parser, and a dialogue module. The dialogue module has a calendar of available system and user times, a partial history of system goals, and a preference stack to keep track of the focus of the conversation. The dialogue module uses rules to interpret the user's input , make an appropriate response, and provide a prediction (grammar) of the user's next response for the speech recognizer. Rules also determine when the system grabs the initiative from the user.