Rousseau follows this tradition, which has passed into common sense, when he writes. Languages are made to be spoken: writing serves only as a supplement to speech. Here Derrida intervenes, asking what is a supplement? Webster's defines supplement as something that completes or makes an addition'. Does writing complete speech by supplying something essential that was missing, or does it add something that speech could perfectly well do without? Rousseau repeatedly characterizes writing as a mere addition, an inessential extra.