A Phenomenological Study on Teachers’ Lived Experiences of Their English Medium Instruction (EMI) Implementation in Thai Secondary Schools

This descriptive phenomenological study investigates how Non-Native English-Speaking (NNES) subject teachers (n = 9) who implemented English Medium Instruction (EMI) in their teaching across the English Program (EP), the Intensive English Program (IEP), and the Science-Mathematics Bilingual Program (SMBP) experienced their work. While existing EMI research has largely focused on language outcomes, policy implementation, and higher education settings, this study addresses a significant gap by exploring the subjective realities and professional vulnerabilities of secondary-level teachers in a Southeast Asian context. Grounded in Husserl’s philosophical framework, this research uses in-depth phenomenological interviews and classroom observations to examine the essence of teaching content through a non-native language. Data were analyzed through horizontalization, clustering of meaning units, and the development of textural and structural descriptions. The findings revealed that EMI implementation is a complex professional journey for NNES subject teachers, involving linguistic-pedagogical dissonance, impact on teacher identity and practice, emotional and cognitive load, and the adoption of adaptive teaching practices. However, this experience also provides NNES subject teachers with professional growth in adaptive pedagogical expertise, multimodal and translanguaging strategies, and teacher resilience. This study is original in its systematic phenomenological documentation of how NNES secondary teachers reconstruct their professional identities. It reveals their transition from content specialists to multilingual mediators through reflective meaning-making, a process largely invisible in policy-oriented and higher-education-focused EMI research. Implications include designing contextually responsive professional development and translanguaging-informed policy support for EMI teachers across Southeast Asian secondary education.