Language in its broad sense refers to a message system communicated from one to another. It is not uncommon for teachers to teach with a specific kind of language to pupils, which creates unequal relations of power, particularly between teachers and pupils in classroom context. In turn, language itself becomes a discourse including the ways teachers speak during PE lessons. This study investigates the language used by two student teachers in PE lessons during field experience in a primary school in Hong Kong. The PE lessons conducted by the participants were video taped and analysed in the aspects of context, teaching process, and most of all, the language used during the lessons. Results indicate that the participants used language to teach and control pupils learning and discipline consciously and unconsciously. As student teachers, their teaching behaviour and performance were much influenced by the school traditions, such as routine training. However, through languages during the process of teaching, they exercised power and control over their pupils on thinking and ways of problem solving. Hidden curriculum such as sexism also existed unconsciously as another discourse in the lessons.