When students get their mathematics correct can teachers be sure that they really know what they are doing or have the developed strategies that enable them to answer problems but are never quite sure if the answers are correct or what they actually mean? This issue is a perennial one in mathematics education and has been seen to arise from the teaching of school mathematics as a set of skills and procedures that often have little or no meaning to students. In this paper, the author proposed that there is a need to pay attention to the language of mathematics in order to investigate critically students' deep understandings. For too long, school mathematics was seen to be a discipline different or even divorced from language. After all, there is a widely held perception that students that do not have a strong background in English can still do mathematics, which gives support to the notion that the two disciplines are discreet to a significant extent. The author considers what constitutes mathematical literacy.