While slang may be condemned by purists and schoolteachers, it should be remembered that it is a monument to the language´s force of growth by creative innovation, a living example of the democratic normally anonymous process of language change, and the chief means whereby all the languages spoken today have evolved from earlier tongues. Mario Pei, The Story of Language, 1949.Conocer exclusivamente un idioma vivo en sus rígidos modes académicos es conocerle a medias; es tratarle como a esas lenguas muertas cuyos fturos sólo es dado recoger a limitado número de eruditos. Luis Besses, Diccionario de argot francés, 1903