The Effects of CLIL on Enhancing EFL Writing Accuracy and Language Learning Motivation in an Indonesian Vocational High School Setting

Writing accuracy remains a persistent challenge for EFL students in Indonesian vocational high schools, where grammar instruction is often decontextualized. Additionally, low language learning motivation further impedes proficiency, as conventional non-CLIL methods fail to provide meaningful engagement. Content and Language Integrated Learning (CLIL) presents a pedagogically sound alternative, merging subject content with language acquisition to create an interactive and cognitively enriching learning environment. This study explores the efficacy of CLIL in enhancing writing accuracy and language learning motivation among third-grade vocational high school students in Aceh, Indonesia. Employing a mixed-methods, quasi-experimental design, the 12-week intervention integrated CLIL-based lesson plans and e-modules adapted from the national curriculum. The instructional approach emphasized linguistic structures such as cause-and-effect clauses, active and passive voice, modal auxiliaries, and selected tenses (present, past perfect, and future tenses), with structured activities strategically designed to foster motivation. A total of 44 students participated. Writing accuracy was assessed using the Barkovska EFL CLIL assessment grid, while language learning motivation levels were measured through a structured questionnaire. Statistical analyses—including paired t-tests, 95% confidence intervals, and effect size computations—revealed minimal, non-significant differences between the experimental and control groups. These findings suggest that while CLIL enhances learner engagement, further pedagogical refinement and targeted teacher training are essential to optimize its impact on measurable language proficiency outcomes in vocational EFL settings.