Intensity matters in CLIL: Evidence from primary school learners' receptive skills

The implementation of L2-medium education, exemplified by Content and Language Integrated Learning (CLIL), is becoming increasingly popular in primary schools (Garcia Mayo, 2021). While previous research highlights CLIL's positive impact on linguistic competence (Jime<acute accent>nez-Catala<acute accent>n & Ruiz de Zarobe, 2009), differences in linguistic achievement are often associated with varying exposure hours (Pladevall-Ballester & Vallbona, 2016). Despite CLIL's growing popularity, studies examining linguistic achievement in varying-intensity CLIL programs remain scant. We address this gap by comparing low and high-intensity CLIL programs, alongside a standard English as a foreign language (EFL) program in primary schools. Focused on 11-year-olds' receptive skills, our results show that high-intensity programs significantly enhance proficiency in listening and reading when compared to their lower-intensity counterparts. Distinctions between low-intensity and EFL programs are non-significant. These findings underscore the critical role of the intensity of exposure in shaping the effectiveness of CLIL programs and contribute insights for refining CLIL program design guidelines.