This paper gives a systematic approach to what is possible with computer assisted language learning (CALL) materials. They cannot replace teachers but are a source of additional material that the learner controls because of the computer’s restricted ability compared to humans to simulate conversation.

The CALL programs are classified according to their design (i.e., the way they give stimuli and the expected responses of the learner). This paper lists the possible basic manipulations that are offered by the programs, for example, deletion, insertion, reordering, substitution, translation, and rephrasing. It also summarizes basic concepts of CALL materials and gives a good survey of the features of existing CALL programs.

The types of help procedures include indirect help, which might possibly be useful for the learner but might not be asked for. Also included are standards of presentation, which should follow the possibilities of the computers and fulfill the expectations of the users who often already know what can be done in this field from their experience with computer games. Finally, there are suggestions of what material should be offered more often by the programs (e.g., dictionary packs).

The author gives the promised information in a clear and distinct way and as succinctly as possible. He indicates where further information can be obtained. This paper can be recommended for all who intend to use or to design CALL materials.