ABSTRACT
The great promise of content and language integrated learning (CLIL) is that it will enhance learners’ language competence beyond what is possible in regular language classes. In this chapter, we will review empirical research that has investigated this claim. While a first generation of studies tended to find positive effects throughout, recent results have been more mixed. Reasons for this shift lie in methodological advances (e.g., better statistics, larger samples, better matched cohorts), deliberate attention to the selection bias linked to many CLIL implementations, and a wider range of CLIL contexts investigated. For this reason, we will focus on recent empirical research published between 2015 and 2021, examining the effect of CLIL on vocabulary, grammar, listening, reading, speaking, and writing. Our review shows that CLIL research has become more sophisticated and results more differentiated, creating an evidence-base for better-tailored CLIL implementations. For example, our findings suggest that it is not merely the extra exposure but also the meaning-focused nature of CLIL instruction that drives linguistic development. Yet, it appears that the pedagogical design pays a crucial role, as learner-centred, cognitively engaging approaches, and settings that include some explicit instruction lead to more favourable results.
