Ferdinand de Saussure was a Swiss linguist considered the father of linguistics. He taught courses on Sanskrit, Gothic, Old High German, and Indo-European languages at the University of Geneva. Saussure developed the concepts of langue and parole, the system of a language and its usage, and emphasized the arbitrary nature of the linguistic sign. He viewed language as a system of relations and differences that is studied through both synchrony, the present state, and diachrony, its historical development.