Our goal is to build a system of 3D animation and facial expressions of emotion correlated with the intonation of the voice. Up till now, the existing systems did not take into account the link between these two features. We will look at the rules that control these relations (intonation/emotions and facial expressions/emotions) as well as the coordination of these various modes and expressions. Given an utterance, we consider how the messages (what is new/old information in the given context) transmitted through the choice of accents and their placement, are conveyed through the face. The facial model integrates the action of each muscle or groups of muscles as well as the propagation of the muscles' movement. Our first step will be to enumerate and to differentiate facial movements linked to emotions as opposed to those linked to conversation. Then, we will examine what the rules are that drive them and how their different functions interact.