In this paper, we present the Web-based CALL environment (or WALL) which is currently being experimented with at the University of Paris 13 in the Computer Science Department of the Institut Universitaire de Technologie. Our environment is being developed to teach computer science (CS) English to CS French-speaking students, and will be extended to other languages for specific purposes such as, for example, English or French for banking, law, economics or medicine, where on-line resources are available.

English, and more precisely CS English is, for our students, a necessary tool, and not an object of study. The learning activities must therefore stimulate the students' interest and reflection about language phenomena. Our pedagogical objective, relying on research acquisition (Wokusch 1997) consists in linking various texts together with other documents, such as different types of dictionaries or other types of texts, so that knowledge can be acquired using various appropriate contexts.

Language teachers are not supposed to be experts in fields such as computer sciences or economics. We aim at helping them to make use of the authentic documents that are related to the subject area in which they teach English. As shown in Foucou and Kübler (1998) the wide range of resources available on the Web can be processed to obtain corpora, i.e. teaching material. Our Web-based environment therefore provides teachers with a series of tools which enable them to access information about the selected specialist subject, select appropriate specialised texts, produce various types of learning activities and evaluate students' progress.

Commonly used textbooks Tor specialised English offer a wide range of learning activities, but they are based on documents that very quickly become obsolete, and that are sometimes widely modified. Moreover, they are not adaptable to the various levels of language of the students. From the students' point of view, working on obsolete texts that are either too easy or too difficult can quickly become demotivating, not to say boring.

In the next section, we present the general architecture of the teaching/learning environment; the method of accessing and using it, for teachers as well as for students, is then described. The following section deals with the actual production of exercises and their limits. We conclude and present some possible research directions.