Abstract
In today’s globalized world, the effective use of academic language is essential for students' success in education and future careers. Content and Language Integrated Learning (CLIL) methodology integrates subject content with language learning, fostering the development of academic language proficiency alongside subject-specific knowledge. In chemistry education, CLIL has the potential to improve teaching and learning outcomes while preparing  students of 12 grades for external chemistry exams conducted in English, especially when prior instruction is in Russian or Kazakh.

This study investigates the impact of CLIL on the development of academic language skills and the quality of chemistry education. A mixed methods approach was employed, combining quantitative data from a survey of 83 chemistry teachers across Kazakhstan and qualitative data from interviews with 12 Nazarbayev Intellectual School (NIS) teachers. The survey assessed awareness, attitudes, and CLIL practices, while interviews explored experiences, challenges, and recommendations for implementation.

To evaluate CLIL's effectiveness, 66 students in grades 11 and 12 were divided into two groups: a control group taught traditionally and an experimental group taught using CLIL. The results showed that CLIL positively affects students' understanding of chemistry concepts and their academic language use in scientific contexts. However, gaps in teacher training and resource availability were identified as challenges to effective implementation.

Literature Review

     CLIL integrates subject content with foreign language learning and fosters both cognitive and linguistic development (Coyle et al., 2010). This approach is particularly beneficial in chemistry, where mastering academic language is essential. Dalton-Puffer (2011) highlights how CLIL enhances terminology usage, complex sentence construction, and critical thinking—skills crucial for chemistry, which involves scientific texts and problem-solving. Marsh (2012) emphasizes the motivational environment created by CLIL, as students see practical applications of language in scientific contexts. Meyer (2013) found that students in CLIL-based chemistry lessons understood complex topics better than those in traditional lessons. Goris et al. (2019) showed that CLIL promotes skills in analysis, synthesis, and application of knowledge. However, Llinares and Morton (2017) caution that teacher training is vital for successful implementation, as many educators face difficulties integrating language and content. A lack of methodological guidance and resources further limits CLIL's effectiveness.

Overall, research indicates that CLIL enhances academic language development and education quality in chemistry. Yet, it underscores the need for more research and teacher support.

Research Objectives

1. Analyze theoretical foundations of CLIL implementation in chemistry.
2. Evaluate the effectiveness of CLIL-based materials for academic language and chemistry content.
3. Develop and implement CLIL-based lesson plans for grades 11 and 12.
4. Conduct an experimental study comparing traditional and CLIL-based lessons.
5. Analyze results to assess CLIL's impact on academic language and chemistry education.

In this study, mixed methods research was carried out to identify the impact of using Content and Language Integrated Learning (CLIL) technology on the academic language development and quality of chemistry education among students. The rationale for this approach is that a combination of qualitative and quantitative methods provides a deeper understanding of the research problem compared to a single approach (Johnson & Onwuegbuzie, 2004). Some scholars view mixed methods research as a methodology based on philosophical assumptions (Tashakkori & Teddlie, 1998), using induction (discovery of patterns), deduction (theory testing), and abduction (selecting the best explanations for results) as its core logic (deWaal, 2001). Other scholars emphasize data collection and analysis methods (Creswell et al., 2003). The dual nature of this method ensures a comprehensive understanding of the research problem, particularly in contexts where a single perspective is insufficient. The study used qualitative methods such as interviews, lesson observations, and document analysis, while quantitative data was gathered through a questionnaire. Qualitative research explained and generalized the quantitative findings. The aim of the study was to assess how integrating CLIL into chemistry lessons affects students' mastery of academic language and subject-specific content. Object of Study: Students in grades 11 and 12. Participants were divided into a control group (traditional teaching methods) and an experimental group (CLIL-based teaching). The relevance of the study lies in the growing demand for students to develop interdisciplinary skills, particularly in academic language and STEM subjects. By combining language learning with chemistry, CLIL addresses critical challenges, including the abstract nature of chemistry concepts and the need for proficiency in scientific terminology. CLIL lessons also prepare students for future academic and professional environments, where the ability to think critically, plan independently, and communicate effectively is essential. The study was conducted during the first semester of the 2023-2024 academic year at Nazarbayev Intellectual School of Chemical and Biological Studies in Petropavlovsk, Kazakhstan. A total of 66 students participated: 20 12-grade students and 46 11-grade students. The experimental group consisted of students with low motivation and limited academic language proficiency, aiming to test the hypothesis that CLIL technology would enhance their learning outcomes. By integrating subject-specific content and language learning, the study highlights the potential of CLIL to address both linguistic and academic challenges in chemistry education, offering a comprehensive solution to modern educational demands.

The study aimed to investigate the impact of using Content and Language Integrated Learning (CLIL) technology on the development of academic language skills and the quality of chemistry education among students in grades 11 and 12. The analysis of data collected from surveys, interviews, and experimental study highlighted the following key findings: • Improved Academic Language Proficiency • Students in the experimental group, who were taught using the CLIL approach, demonstrated a significant improvement in their academic language skills. This included enhanced vocabulary acquisition, the ability to construct complex sentences, and better understanding and usage of scientific terminology. In contrast, students in the control group, who followed traditional teaching methods, showed moderate progress in these areas. • Enhanced Understanding of Chemistry Concepts • The experimental group achieved higher scores in assessments that measured their understanding of complex chemistry topics, such as reaction mechanisms and stoichiometry. These results indicate that integrating language and content learning facilitated a deeper comprehension of subject-specific material. • Increased Student Motivation and Engagement • Qualitative data from teacher interviews revealed that students in the experimental group were more motivated and engaged during lessons. They expressed a greater interest in chemistry as they could see the practical application of academic language in real-world scientific contexts. • Challenges in Implementation • Despite the positive outcomes, the study identified challenges that hindered the full realization of CLIL's potential. These included a lack of training for teachers to effectively implement the approach, limited availability of CLIL-specific resources, and time constraints in planning and executing CLIL-based lessons. • Teacher Perspectives on CLIL • Survey results showed that 72% of teachers recognized the value of CLIL in improving both language and subject knowledge. However, 64% reported needing additional support, such as professional development programs and methodological guidance, to implement CLIL effectively.

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