Can translanguaging space be constrained? A moment analysis of an IELTS speaking teacher’s translanguaging practices in online teaching videos

• The study fills a gap by examining translanguaging spaces in online videos, including their affordances and constraints. • Methodologically, it adopts moment analysis to examine participant-identified translanguaging moments. • Findings show online teaching can form a translanguaging space where teachers mobilise full repertoires to support learning. • This space is constrained by video media and the teacher’s talking-head formats, limiting multimodality and interactive translanguaging. Despite extensive research on translanguaging in school classrooms, studies situated in the context of online videos remain scarce. This study examines an online English teaching video through a translanguaging lens, focusing on the construction process, affordances, and constraints of the translanguaging space. Data include observations of viewers’ real-time responses and stimulated-recall interviews with four learners. Moment analysis was used to examine translanguaging moments highlighted by participants. Findings suggest that online teaching videos can constitute a translanguaging space where teachers mobilize their full linguistic repertoire to support content learning. The teacher’s embedding of key English expressions, cross-varietal and multimodal shifts, and integration of external knowledge facilitate knowledge construction. However, the translanguaging space is constrained by the video medium and teacher’s “talking head” video style: spatial constraints limit multimodal actions, and the teacher-centered monologic video format further reduces opportunities for interactive translanguaging. This study could contribute to a nuanced understanding of translanguaging in online contexts and have implications for developing online teaching materials.