A form-based dialogue manager for spoken language applications

A popular approach to dialogue management is based on a finite state model, where user utterances trigger transitions between the dialogue states, and these states, in turn, determine the system's response. The paper describes an alternative dialogue planning algorithm based on the notion of filling in an electronic form, or "E-form". Each slot has associated prompts that guide the user through the dialogue, and a priority that determines the order in which the system tries to acquire information. These slots can be optional or mandatory. However, the user is not restricted to follow the system's lead, and is free to ignore the prompts and take the initiative in the dialogue. The E-form based dialogue planner has been used in an application to search a database of used car advertisements. The goal is to assist the user in selecting, from this database, a small list of cars which match their constraints. For a large number of dialogues collected from over 600 naive users, we found over 70% compliance in answering specific system prompts.