'You can speak German, sir': on the complexity of teachers' L1 use in CLIL

Classroom code switching in foreign language teaching is still a controversial issue whose status as a tool of both despair and desire continues to be hotly debated. As the teaching of content and language integrated learning (CLIL) is, by definition, concerned with the learning of a foreign language, one would expect the value of code switching to constitute an important part in CLIL research. This paper sets out to argue that the use of the majority language in CLIL by teachers follows an educationally principled approach. It is expressed within an instructive and regulative register, motivated by behavioural, classroom and task management, and knowledge scaffolding considerations. Through a comparative data coding process using MAXQDA, several dimensions of code switching were identified and elaborated on. These dimensions included principledness, contextualisation, conflictuality, domain sensibility, linguistic deficit awareness, language learning, and knowledge construction support, as well as affectivity. Taking this complex web as a reference point, the paper ends proposing six theses on code switching and recommending its relevance to CLIL teacher training.