Abstract Emotional expressivity in singing is examined by comparing neutral and expressive performances of a set of music excerpts as performed by a professional baritone singer. Both the neutral and the expressive versions showed considerable deviations from the nominal description represented by the score. Much of these differences can be accounted for in terms of the application of two basic principles, grouping, i.e. marking of the hierarchical structure, and differentiation, i.e. enhancing the differences between tone categories. The expressive versions differed from the neutral versions with respect to a number of acoustic characteristics. In the expressive versions, the structure and the tone category differences were marked more clearly. Furthermore, the singer emphasized semantically important words in the lyrics in the expressive versions. Comparing the means used by the singer for the purpose of emphasis with those used by a professional actor and voice coach revealed striking similarities.