This article presents an overview of a long-term research work with a rule system for the automatic performance of music. The performance rules produce deviations from the durations, sound levels, and pitches nominally specified in the music score. They can be classified according to their apparent musical function: to help the listener (I) in the differentiation of different pitch and duration categories and (2) in the grouping of the tones. Apart from this, some rules serve the purpose of organizing tuning and synchronization in ensemble performance. The rules reveal striking similarities between music performance and speech; for instance final lengthening occur in both and the acoustic code used for marking of emphasis are similar.
