Content and Language Integrated Learning (CLIL) has gained increased attention as a pedagogical link between conceptual and language development due to the combined demands for STEM competency and multilingual competence. Using empirical studies published, this systematic review investigates whether CLIL improves students' disciplinary vocabulary and scientific literacy in STEM education. Sixty-two studies were found in major databases and coded according to pedagogical, design, and context factors. The results consistently show that CLIL learners outperform their classmates who are not CLIL in terms of conceptual understanding and scientific communication. When training clearly combines language objectives with disciplinary activities like reasoning, debate, and modeling, the biggest advances take place. A deeper conceptual engagement is supported by evidence that suggests multimodal scaffolding, translanguaging techniques, and cognitively productive classroom discourse reduce the risk of cognitive overload. Uneven resource access and a lack of teacher experience with dual-focus design, on the other hand, continue to be obstacles. According to the review's findings, CLIL can effectively promote scientific literacy when language is viewed as a cognitive tool for disciplinary thinking rather than just a teaching medium. A reporting checklist and a scaffolded CLIL-STEM framework are suggested to direct further study and application. The implications for curriculum development, teacher preparation, and educational policy that aim to promote integrated literacy in science are examined.

Content-language integration, translanguaging, multimodality

Airey, J. (2022). Disciplinary literacy and the role of language in the learning and teaching of science. International Journal of Science Education, 44(7), 1032–1051. https://doi.org/10.1080/09500693.2022.2043345

Cheung, K. K. C., & Ng, D. T. K. (2025). A systematic review of translanguaging in STEM education. International Journal of Multilingualism, 22(1), 1–23. https://doi.org/10.1080/14790718.2025.2512783

Dalton-Puffer, C. (2011). Content-and-language integrated learning: From practice to principles? Annual Review of Applied Linguistics, 31, 182–204. https://doi.org/10.1017/S0267190511000092

García, O., & Wei, L. (2014). Translanguaging: Language, bilingualism and education. Palgrave Macmillan.

Huang, Y.-C., Chang, C.-W., & Lin, Y.-J. (2020). The effects of CLIL on elementary students’ science learning and vocabulary development. Journal of Language Teaching and Research, 11(2), 246–258. https://doi.org/10.17507/jltr.1102.03

Karampali, D.-E., Tiberghien, A., & Chatzopoulos, D. (2025). Integrating language and content in STEM: A framework for scientific literacy. In Advances in STEM Education (pp. 85–104). Springer. https://doi.org/10.1007/978-3-031-56712-1_5

Lai, C.-J., Wang, Y.-H., & Chen, C.-H. (2024). Hands-on content and language integrated learning: Effects on vocabulary and procedural knowledge. Humanities and Social Sciences Communications, 11(3), 1201. https://doi.org/10.1057/s41599-024-03960-z

Martínez-Soto, T., Pérez, M. J., & Rebolledo, D. (2023). The role of ICT and CLIL in STEM education: A systematic review. Education Sciences, 13(1), 73. https://doi.org/10.3390/educsci13010073

Mercer, N., & Dawes, L. (2014). The study of talk between teachers and students, from the 1970s until the 2010s. Oxford Review of Education, 40(4), 430–445. https://doi.org/10.1080/03054985.2014.934087

Meyer, O., Coyle, D., Halbach, A., Schuck, K., & Ting, T. (2015). A pluriliteracies approach to teaching for learning: Putting a pluriliteracies approach into practice. The Language Learning Journal, 43(1), 64–79.https://doi.org/10.1080/09571736.2013.869938

Mortimer, E. F., & Scott, P. H. (2003). Meaning making in secondary science classrooms. Open University Press.

Nystrand, M. (2006). Research on the role of classroom discourse as it affects reading comprehension. Research in the Teaching of English, 40(4), 392–412.

Piacentini, V. (2022). CLIL and science education: A review for a language focus in science teaching. Journal of Science Education and Technology, 31(6), 843–860. https://doi.org/10.1007/s10956-022-09995-7

Pittas, E., & Kyriakou, K. (2024). A systematic review of student learning outcomes in programs teaching school subjects through languages other than English. Frontiers in Education, 9, 1447270. https://doi.org/10.3389/feduc.2024.1447270

Reitbauer, M., Llinares, A., Morton, T., & Whittaker, R. (2018). Towards a cognitive-linguistic turn in CLIL. Latin American Journal of Content and Language Integrated Learning (LACLIL), 11(1), 9–32. https://doi.org/10.5294/laclil.2018.11.1.2

Roth, T., Langer, A., & Kuhn, J. (2022). Content and language integrated scientific modelling in physics classrooms. Frontiers in Education, 7, 922414. https://doi.org/10.3389/feduc.2022.922414

Roth, T., Wessels, A., & Kuhn, J. (2024). Balancing STEM knowledge and language proficiency: A CLIL perspective. International Journal of Science Education, 46(4), 567–586. https://doi.org/10.1080/09500693.2023.2232502

Roussel, S., Tricot, A., & Sweller, J. (2017). Cognitive load theory and content and language integrated learning. Computers & Education, 117, 172–183. https://doi.org/10.1016/j.compedu.2016.12.010

Sweller, J. (2011). Cognitive load theory. Psychology of Learning and Motivation, 55, 37–76. https://doi.org/10.1016/B978-0-12-387691-1.00002-8

Tagnin, L., Alves, A., & Prado, C. (2021). Building science through questions in CLIL classrooms. International Journal of STEM Education, 8(1), 23. https://doi.org/10.1186/s40594-021-00293-0

Hazratqulova, E. I. Q., & Botirova, S. I. (2024). PSIXOLINGVISTIK ASPEKTLARINING XORIJIY TILLARNI O ‘QITISHDA TURLI ZAMONAVIY METODLARDA QO ‘LLANISHI. Academic research in educational sciences, 5(CSPU Conference 1), 627-633.

Isroilova, T. (2024). Analyzing language use through corpora in different contexts. Mental Enlightenment Scientific-Methodological Journal, 5(08), 126-135.