This study investigated potential inequalities in a bilingual education program where secondary school students are streamed into two strands with different degrees of exposure to the target language based on their proficiency: high exposure (HE) and low exposure (LE). Drawing on classroom registers (Christie, 2005), appraisal theory (Martin & White, 2005), and sociocultural perspectives on classroom interaction (Gibbons, 2006; Lemke, 1989; Mortimer & Scott, 2003), researchers analysed interactional practices by teachers teaching the same content in both groups. Results show no major differences in distribution of classroom registers and teachers' general pedagogical purposes across groups. Analysis of students' language use across registers corroborates previous studies showing that translanguaging in content and language integrated learning is more common when the focus is on classroom management issues (e.g., Moore & Nikula, 2016). The most striking results relate to differences in use of pedagogical purposes and evaluative language. These differences entail more interactional engagement in higher order thinking skills by HE students and use of a wider variety of language resources in the second language (L2) to express these meanings, compared to LE students. This indicates that the division into strands in bilingual programs may lead to different perceptions of students' academic capacities beyond L2 proficiency and reinforcement of social differences and inequality in bilingual programs.