In this linguistic ethnography of bilingual science learning in a South African high school, the author connects microanalyses of classroom discourse to broader themes of de/coloniality in education. The book challenges the deficit narrative often used to characterise the capabilities of linguistically-minoritised youth, and explores the challenges and opportunities associated with leveraging students' full semiotic repertoires in learning specific concepts. The author examines the linguistic landscape of the school and the beliefs and attitudes of staff and students which produce both coloniality and cracks in the edifice of coloniality. A critical translanguaging lens is applied to analyse multilingual and multimodal aspects of students' science meaning-making in a traditional classroom and a study group intervention. Finally, the book suggests implications for decolonial pedagogical translanguaging in Southern multilingual classrooms.