A discourse system for conversational characters

This paper describes a discourse system for conversational characters used for interactive stories. This system is part of an environment that allows learners to practice language skills by interacting with the characters, other learners, and native speakers using instant messaging and email. The dialogues are not purely task oriented and, as a result, are difficult to model using traditional AI planners. On the other hand the dialogues must move the story forward and, thus, systems for the meandering dialogues of chatterbots (for example, AliceBot) are not appropriate. Our approach combines two methods. We use the notion of dialogue game or speech act networks [1][2] to model the local coherence of dialogues. The story moves forward from one dialogue game to another by means of a situated activity planner [3].