This paper presents a plan-based model that handles negotiation subdialogues by inferring both the communicative actions that people pursue when speaking and the beliefs underlying these actions. We contend that recognizing the complex discourse actions pursued in negotiation subdialogues (., expressing doubt) requires both a multistrength belief model and a process model that combines different knowledge sources in a unified framework. We show how our model identifies the structure of negotiation subdialogues, including recognizing expressions of doubt, implicit acceptance of communicated propositions, and negotiation subdialogues embedded within other negotiation subdialogues. .
