This article argues that mathematical competence in the sense of "mathematical literacy" (OECD 2003) includes linguistic and communicative (partial) competences. It is therefore necessary when developing competence expectations of pupils in mathematics to take into consideration previous knowledge and development in this area also. It is possible to develop checklists of cognitive-linguistic capacities on the basis of an analysis of concrete descriptions of mathematical competence underpinning mathematical educational standards (example HarmoS project in Switzerland). At the same time it also becomes clear that these capacities at least to some extent are not simply preconditions but also integral components of mathematical competence. The ability to understand and articulate in language various modes of mathematical thinking is the aim of mathematical teaching and at the same time a possible contribution of the subject to the development of language awareness and plurilingual competence.