We view communication as action aimed at increasing the efficiency of interaction among multiple agents. Thus, we postulate that a speaker design a speech act so as to maximally increase the benefit it obtains as the result of the interaction. This paper presents a theoretical framework which can be used by this kind of the design process. Our framework consists of a representation of an episteinic state of an agent engaged in an interaction, and includes the agent’s preferences, abilities and beliefs about the world, as well as the beliefs the agent has about the other agents, the beliefs the other agents have, and so on. A pragmatic meaning of a speech act can be then defined as a transformation it induces on the epistemic state of an agent. This transformation leads to a change in the quality of the interaction, expressed in terms of the benefit to the agent. We propose that a rational communicative behavior results from a speaker choosing to perform the speech act that maximizes the expected increase in the quality of the interaction. In this paper we analyze questions, proposals and threats, imperatives, and statements of knowledge and belief.