Language teacher identity (LTI) and language teacher agency (LTA) have been recently recognised as important research topics in the English language teaching (ELT) field as English language teachers encounter the impact of educational technology, multilingualism, and globally marketized ELT education. The TESOL Quarterly (Varghese et al., 2016) and Modern Language Journal (de Costa & Norton, 2017) have devoted special issues to language teacher identity, and many researchers have published studies on language teacher identity and agency in relation to educational policy (Glasgow & Bouchard, 2019; Liddicoat & Taylor-Leech, 2021), classroom interaction (Bonacina-Pugh, 2020; Kayi-Aydar, 2015), community of practice (Yazan, 2018), CLIL and bilingual education (Bonnet & Breidbach, 2017; Moate & Ruohotie-Lyhty, 2020).

This thesis further situates LTI and LTA research in the Taiwanese language planning and policy context, aiming to investigate the construction of Taiwanese English language teacher professional identity and agency in multilingual and multimodal times. This thesis adopted a linguistic ethnography research design to examine how English language teachers were positioned by structural policies and how teachers positioned themselves and others in their daily narratives and classroom interactions. The data were collected from four policy documents, four participant teachers’ interviews, reflective posts, and classroom observations.

The findings show that each participant teacher faced context-specific affordances and constraints in translating the policy and curriculum into their teaching practices. Language teacher identity and agency are neither pre-determined nor uniform but rather are constantly shifting across different micro contexts. The comparison of the four case teachers also illustrates how language teacher identity and agency are configured individually and collectively. The four teachers’ flexible strategies for digital teaching and code-switching to L1 emerged from their community of practice and teaching beliefs. Their contextualised teaching practices took shape in reaction to the major policy and curriculum changes. The findings also suggest that the four case teachers showed little awareness of the impact of structural factors on their identity and agency construction. Finally, implications for classroom teachers, language teacher educators, language policymakers, and researchers are provided.