In a CALL-environment (Computerassisted language learning) programs should ideally allow the learner to train his/her communicative competence, which is one of the main goals of foreign language teaching nowadays. This can be reached by allowing learners to use and train their knowledge of a foreign language in realistic dialogue-style exercises. All levels of linguistic and communicational analysis have to be considered to realize such a system. In this paper I will concentrate on the dialogue component of the concept, which relies on two main knowledge sources. .
