Literacy is considered one of the major goals of education. In this article the author argues for the contribution of mathematics teaching in general language achievement. Syntactical aspects as often not given enough care to in language acquisition is naturally paid attention to in mathematics classes when for example analysing typical calculation mistakes. Organisation of reasoning, which is important for editing one’s solutions of mathematical problems, might help to understand the differences of argumentation and narration, the latter respecting order of time. Furthermore, geometrical exercises ask for graphical as well as theoretical analyses, which cannot be separated from verbal expression. This gives way to connect different cognitive functions.