The intention of this study is to explore mathematical discourse and teaching methods in Grades 6 and 7 of primary school in the Eastern Cape Province of South Africa. The school's student population changed from predominately white English/Afrikaans-speaking learners before the 1994 election to predominately black Xhosa-speaking students in 2004. The language of teaching and learning is strictly English, and most teachers cannot speak or understand Xhosa. Additionally, some Xhosa-speaking learners cannot clearly articulate their thinking and reasoning in English. The study demonstrates two mathematics classroom interactions and illustrates how language plays a pivotal role in classroom discourse. The findings of the study suggest that working with peers in Xhosa may facilitate learners' skills and development of conceptual understanding of mathematics. Furthermore, the study shows that requiring verbal discourse in the classroom to be only in English limited the learners' success in displaying their mathematical understanding, which in turn made them appear to be lower achieving than those who spoke only in English.