Translanguaging as motivational resource for marginalized Vietnamese EMI learners

English-medium instruction expansion in Vietnamese higher education has intensified socioeconomic stratification, yet the motivational and participatory consequences for disadvantaged students remain poorly understood. This explanatory sequential mixed-methods study examined how power dynamics shape disadvantaged students’ L2 motivation and willingness to deploy linguistic repertoires across three Hanoi universities, drawing on survey data from 312 participants and semi-structured interviews with 24 students. Findings revealed disparities across L2 motivational dimensions: disadvantaged students reported lower ideal L2 selves (d = 0.529), higher ought-to L2 self pressures (d = 0.410), and more negative learning experiences (d = 0.612). Classroom power dynamics produced pronounced fear of error exposure among disadvantaged students (d = 1.470), associated with self-censorship; linguistic capital predicted 40.9% of participation variance independently of proficiency. Translanguaging benefits proved conditional, requiring teacher modeling and validation to redistribute classroom voice, as permission alone was insufficient for disadvantaged students. These findings extend L2 Motivational Self System theory by proposing structural access to linguistic capital as a contextual moderator of motivational construct development in stratified EMI settings. EMI programs serving diverse populations require pedagogical restructuring that validates multilingual resources rather than remediating individual students, alongside policy reforms addressing economic barriers to English education before university entry.