Orchestrating Vocabulary Engagement in Secondary EFL Classrooms: Teacher Mediation in English-Subtitled Video Lessons

Abstract

The growing use of audiovisual resources in English as a Foreign Language (EFL) classrooms has encouraged teachers to incorporate videos with English subtitles into everyday instruction. Although earlier studies suggest that subtitles may support vocabulary development, most have treated subtitles primarily as a form of input enhancement and evaluated their effects mainly through post-test outcomes. Far less attention has been paid to the classroom work through which teachers make subtitled input instructionally useful. In real lessons, subtitles do not operate as self-contained learning tools; their value depends on how teachers focus attention, support meaning-making, and create opportunities for subsequent language use. This study explores teacher mediation in subtitle-based vocabulary work in three Vietnamese upper-secondary EFL classrooms. The dataset comprised six classroom observations, learner interviews (n = 9), one teacher interview, and learner reflection forms (n = 60). Using thematic analysis, the study examined how teachers shaped learners’ encounters with vocabulary across pre-viewing, viewing, and post-viewing stages. Four recurring mediation practices were identified. Teachers first signalled which lexical items were worth attending to before the video began. They then guided learners’ interpretation of unfamiliar words through questioning and contextual discussion. After viewing, they designed tasks that required students to revisit and use target vocabulary in new utterances. They also managed lesson timing by deciding when to pause the video and when to preserve viewing continuity. The study shows that vocabulary learning in subtitled video lessons is not produced by textual support alone. Rather, it emerges through classroom orchestration, in which teacher mediation plays a key role in shaping attention, interpretation, and reuse. The findings contribute to work on multimodal language teaching by clarifying the instructional conditions under which subtitles become productive resources for vocabulary development.