Ouhao Chen

Background Previous research in the field of content and language integrated learning (CLIL) has not yet comprehensively investigated the interaction between learners' expertise and the instructional effectiveness. Aims Taking cognitive load theory as the theoretical framework, a study was conducted to investigate the expertise reversal effect on learning English and mathematics simultaneously: whether an integrated approach (i.e. learning both English and mathematics simultaneously) could facilitate the acquisition of mathematic skills and English linguistic skills as a foreign language more effectively and efficiently than a separated learning approach (i.e. learning Mathematics and English separately). Materials The materials for the integrated learning approach were in English‐only, and the materials for the separated learning approach were in English‐and‐Chinese. Both sets of materials were given as reading content for teaching mathematic skills and English as a foreign language. Methods The study adopted a 2 (language expertise: low vs. high) × 2 (instruction: integrated vs. separated) between‐subject factorial design with instructional approaches and learners' expertise in English as independent variables, the learning performance in Mathematics and English with the cognitive load ratings as the dependent variables. Sixty‐five Year‐10 students with lower expertise in English and 56 Year‐2 college students with higher expertise in English in China were recruited and allocated to two instructional conditions respectively. Results An expertise reversal effect was confirmed: the English and mathematics integrated learning approach was more effective for higher expertise learners while the English and mathematics separated learning condition was more beneficial for lower expertise learners.