This research work is situated at the crossroads of the didactics of Languages and Cultures and CALL (Computer-Assisted Language Learning) via blended learning courseware systems. It focuses on the learners’ usage of computer-mediated learning environments for foreign languages. The premise is that research on usage constitutes a means for course designers to apprehend the ways learners adapt to these tools. Our hypothesis is that there is a discrepancy between the usage prescribed by the teachers and the real usage made by the learners. We believe that it is therefore relevant, from a didactic perspective, to work on these discrepancies so that teacher-designers can improve their practices of these learning systems by adapting their usage models ahead of the implementation of the course setup and by reacting in a more appropriate way during the time the learners are using the tools. This hypothesis raises two main research questions. On the one hand, what use do foreign language learners make of blended learning systems? And, on the other hand, what particular information on usage will help courseware designers in the design or update of their system?The research can be described as experimental action research. This is performed in two research fields: a French context, which is the analytical field and a Malagasy context, which is the field of design and experimentation. These two fields share some common points: a target group of non-specialist language students and specialists of other disciplines enrolled in the first year of their courses and the learning of the target language taking place on a distancelearning platform. Two forms of research data are utilised in both of these fields: invoked data (learners’ traces left on the platform) and raised data (questionnaires completed by the learners and semi-guided interviews of teacher-designers in order to better understand the prescribed uses). The results are of three kinds. At the hermeneutic level, the research enables learners’ usage to be characterised according to their ways of interpreting and adapting to the system. At the praxeological level, it supports the design of courseware systems by giving advice which underlines the role of scenario design and the importance of the strategic use of the tools available to the learner for the tasks proposed. Finally, it helps promote and disseminate the French language to Malagasy students.