The aim of this book is to establish a general theory of communication on the basis of a functional dialogic speech act taxonomy and to apply it to a communicative grammar of the German language. The unit of description is the sequence consisting of action and reaction in the action game. The completely revised second edition develops a new concept of communicative competence which goes beyond a closed system of conventions and can be described as competence-in-performance. The book thus follows a new notion of theory based on probability principles.