Graceful Degradation of Hand Gestures

Embodied Conversational Agents (ECAs) should interact with the user in a reactive way, using non-verbal modalities parallel to speech. Hand gestures, particularly, should be generated on the fly, and precisely timed to speech. However, this does not always succeed. In this short paper we discuss what can be and should be done if the intended gesture cannot be performed in full detail. First we outline the possible shortcomings and problem categories in hand gesturing. Then we give a conceptual description of remedies for time shortage problems. Finally, we report about implementation of graceful degradation of timing, in the framework of our GESTYLE gesture markup language.