Distinction between language and languages is a common structuralist one. Not only can we find it in the hjelmslevian, jakobsonian and benvenistian theories, where it constitutes an axis of elaboration, but what is more inexpected is that it is also present in Martinet’s work, in spite of a sharp criticism of the very notion of language and of the jakobsonian and chomskyan universalist problematics. Saussurean theory shows us that this distinction is inescapable, as soon as language is presupposed instead of being defined. Saussurean definition of language (langue) implies a quite different distinction: between language (langage), the language (langue) and idioms, and this distinction throws a new light on the problematics of general grammar.