Taiwan's 2018 bilingual national policy aims to make the country Mandarin Chinese-English bilingual by 2030. A key component of this policy is the integration of Content and Language Integrated Learning (CLIL), where content subjects are taught through a foreign language (English). This necessitates a significant increase in qualified CLIL teachers, necessitating a robust and sustainable teacher education framework. The current study addresses this need by constructing a Teaching Capability Maturity Model (TCMM) specifically designed for CLIL teachers in Taiwan. The TCMM aims to provide a structured pathway for professional development, enabling teachers to progressively enhance their skills and reach their full potential. The research objectives focus on identifying benchmarks and a framework for the TCMM using a modified Delphi method (MDM), followed by establishing the model's dimensions and framework through Fuzzy Analytic Hierarchy Process (FAHP). The ultimate goal is to contribute to the creation of feasible and sustainable CLIL teacher education in Taiwan, ensuring the success of the nation's bilingual education policy. The study's findings will provide valuable insights into the essential capabilities needed for effective CLIL teaching and offer practical suggestions for curriculum development and teacher training programs.

The study draws upon the Teaching Capability Maturity Model Integration (T-CMMI) developed by Chen and Kuo (2011), which adapts the Capability Maturity Model Integration (CMMI) system for teaching contexts. T-CMMI outlines teaching process areas, goals, and practices, structured into maturity levels (MLs) and capability levels (CLs), allowing for continuous improvement. The researchers also reviewed existing literature on CLIL, including its implementation challenges (McDougald, 2016; Alonso et al., 2008), material development (Bailey, 2015; Banegas, 2016), teacher education (Banegas, 2012; Marsh et al., 2011), and assessment (Pérez and Basse, 2015; Leal, 2016). The European framework for CLIL teacher education (Marsh et al., 2011), which outlines professional competences, modules, and components for CLIL teacher development, served as a significant influence. Taiwan's existing CLIL initiatives, including collaborative teacher training programs and resource materials (Lu and Yuan, 2020; Tsou and Kao, 2018) were also reviewed, providing a Taiwanese context for the development of the TCMM.

A multi-stage approach was employed to construct the TCMM. First, an initial indicator framework was developed through a comprehensive literature review. This framework was then refined using the Modified Delphi Method (MDM). The MDM involved two rounds of questionnaires distributed to 33 experts: 18 primary school teachers, 8 university professors, and 7 pre-service teachers. The experts were selected using purposive sampling to ensure diversity of perspectives and expertise. In the first round, experts evaluated the appropriateness of the framework's components using a 5-point Likert scale, providing feedback and suggestions for improvement. The high response rate (100%) and low quartile deviation (<0.6) indicated strong consensus among experts. The second round used a Fuzzy Analytic Hierarchy Process (FAHP) questionnaire, where experts pairwise compared the relative importance of each level and component in the TCMM using a 9-point scale. FAHP helps account for subjectivity and uncertainty in expert judgment. The consistency of expert opinions was confirmed via the consistency index (CI) and consistency ratio (CR) for each level, ensuring the validity of the results. Microsoft Excel was used for data analysis. The weights derived from FAHP provided a quantitative ranking of the importance of each level and component, facilitating the construction of the final TCMM.

The TCMM comprises five maturity levels (MLs): Initial Level (ML1), Basic Course Management (ML2), Advanced Course Management and Implementation (ML3), Quantitative Management (ML4), and Sustainable Optimization (ML5). Each level contains several components that contribute to CLIL teaching capabilities. The FAHP analysis revealed that the three most important levels were ML2 (Basic Course Management), ML3 (Advanced Course Management and Implementation), and ML1 (Initial Level), accounting for 79% of the total weight. Within ML2, the most important components were content knowledge, curriculum development capability, and content pedagogical knowledge. In ML3, content teaching capability was the most important. In ML1, educational contextual knowledge was the most critical component. The least important levels were ML4 and ML5, indicating that while aspects like multiple assessment and professional development are valuable, foundational skills are paramount, especially in the early stages of CLIL implementation in Taiwan. The consistency index (CI) and consistency ratio (CR) values were below 0.1 for all levels, indicating high consistency and reliability in the expert judgments.

The findings highlight the crucial role of strong course management capabilities (ML2) and practical teaching experience (ML3) in the successful implementation of CLIL. The emphasis on basic course management underscores the need to ensure teachers possess adequate content knowledge of subjects they are teaching in English, along with proficiency in curriculum development and pedagogical approaches specific to CLIL. The importance of the advanced course management and implementation level emphasizes the need for teacher training to focus on hands-on teaching experience and classroom management. The relatively lower weighting given to ML4 and ML5 suggests that while aspects like quantitative assessment and ongoing professional development are essential for long-term effectiveness, acquiring fundamental skills should take precedence, especially during the initial stages of CLIL implementation in Taiwan. The results align with the European framework for CLIL teacher education, indicating a degree of international validity.

This study provides a valuable TCMM for CLIL teachers in Taiwan, identifying key capabilities and prioritizing areas for teacher education and professional development. The model emphasizes the importance of course management skills and practical teaching experience. Future research should incorporate feedback from content teachers to broaden the model's scope and investigate CLIL teacher development across different subject areas and experience levels. Further research could also explore the longitudinal impact of the TCMM on teacher effectiveness and student outcomes.

The study's focus on Taiwanese CLIL teachers and the use of expert opinions through questionnaires may limit the generalizability of findings to other contexts. The reliance on expert judgments might introduce a degree of subjectivity, although the use of the MDM and FAHP mitigated this to some extent. Further, the study did not analyze all possible factors influencing CLIL teacher effectiveness, limiting the scope of the model's comprehensiveness.