Abstract
As English-medium and trilingual instruction expands across higher education in multilingual contexts such as Kazakhstan, understanding effective pedagogical approaches for language development becomes increasingly important. This study examines how project-based Content and Language Integrated Learning (CLIL) influences students’ motivation and English language skill development and compares learners’ perceptions with those of traditional/ classical methods. The participants are third-year English-major students at Korkyt Ata Kyzylorda University in Kazakhstan, who took part in semester-long project-based CLIL classes with Chemistry and Biology as content subjects. A survey-based quantitative study was conducted, and data were examined using descriptive statistics and Pierson’s correlation in SPSS. Findings show that students perceive project-based CLIL as beneficial for speaking and reading skills, with translanguaging practices supporting comprehension, while writing and listening showed comparatively lower gains. A strong positive correlation (r = 0.690, p < .001) between students’ participation in collaborative projects and proficiency gains confirms the importance of interactive and engaging learning environments. It contributes to CLIL theory by foregrounding collaboration as a key component that has been undertheorized in existing frameworks. Despite limitations in sample size and short assessment duration, findings suggest that project-based CLIL with translanguaging elements strengthens both language-learning outcomes and motivation. Practical guidance for curriculum designers and educators implementing CLIL in multilingual educational contexts is also provided.