Under the influence::Using natural language in interactive storytelling

Interacting in natural language with virtual actors is an important aspect of the development of future Interactive Storytelling systems. We describe a paradigm for speech interfaces in interactive storytelling based on the notion of influence. In this paradigm, the user is mainly a spectator who is however able to interfere with the course of action by issuing advice to the characters. This is achieved by recognising corresponding speech acts and mapping them to the plans which implement characters' behaviours in the story. We discuss some examples based on a preliminary, yet fully implemented, prototype