A framework for generating facial expressions from emotional states in daily conversation is described. The framework allows avatars to express the speaker’s state not just prototypical emotions. In this paper, the naturalness of generated facial expressions that are presented together with dialogue speech is examined. An experiment to examine the naturalness of facial expressions presented as still images shows that the two avatars’ facial expressions are almost as natural as manually-made facial expressions. In an experiment to determine the natural display speed of dynamic facial expressions, significant interactions between display speed and emotion group were found for most emotion dimensions.