There is strong evidence that legacies of Apartheid remain in place in South Africa's education system, entangling economic inequality, racial categorization, and de facto language hierarchy. This study draws from an ethnographic study of language diversity in a Cape Town public school, focusing on how classroom practices regulate and school staff frame language diversity and social inequality among their pupils. It uses the concepts of language register, sociolinguistic scale, and racialization to analyze how education policy, classroom practices, and school discourses about language in South Africa implicate class and racial hierarchies. It shows how register analysis reveals multi-scaled connections between linguistic and social inequality. (Language registers, education, social inequality, South Africa)*