Ferdinand de Saussure, who is generally regarded as the founder of structural linguistics, makes a basic distinction between the study of language as parole and of language as langue: as a system. De Saussure's Caurs de linguistique general is the most important of all linguistic works written in Western Europe in the twentieth century. Saussure's major contribution is to theoretical linguistics. Saussure then goes on to treat the notion of value, which is the status of a linguistic unit in relation to other units, from the very existence of which it draws its definition, so that value and identity are two notions that can be equated. Saussure, whose work was known in Kazan, was working along the same lines, and he, who knew no Russian or Polish was acquainted with the Kazan ideas through German translations of two works by Mikolaj Kruszewski. Kruszewski died early and Saussure's lectures were published only after his death by devoted students.