Every body of knowledge has its own language, and most, at the same time, share a common language with the mother tongue. This is true of mathematics, just as it is of biology, art, or French; and it will be the purpose of this article to reflect a bit on the implications of this language area for the secondary school teacher of mathematics. Since there are so many more non-college preparatory students in secondary schools than there are college preparatory students, the point of view here is that of the teacher of the non-college preparatory students.