A computer program is described which takes 'messages' output by a dialogue control module and generates textual and prosodic information to be used in synthesis. Using a unification grammar, a surface structure tree is generated. This tree is so annotated that it is possible to assign potential phrase boundaries on the basis of both syntactic depth and the functional dependencies between constituents. The surface structure further acts as a basis for propagation of focus domains, as a result of which pitch accents may be assigned to individual words.