Racism is pervasive within the lives of racially minoritised pre-service teachers in England, but little work has explored how perceptions about language feature here. Based on interviews and workshops with 26 racially minoritised pre-service teachers, I describe their experiences of language oppression whilst on school experience placements, where they were instructed by mentors to modify, flatten, and completely abandon their ways of talking if they were to be perceived as legitimate. I show how language oppression gets justified by mentors in reference to national policy, and how perceptions about the quality of speech are ideologically anchored to perceptions about the quality of teaching. I show how language oppression often materialises under seemingly benevolent and humanitarian guises, but inevitably maintains the raciolinguistic status quo because it instructs racialised teachers to adapt their speech so that it appropriates whiteness. I argue that language oppression is a key reason why England continues to fail to retain racially marginalised teachers.