Dante Alighieri, De Vulgari Eloquentia ("Concerning Vernacular Eloquence")

Harum quoque duarum nobilior est vulgaris: tum quia prima fuit humano generi usitata; tum quia totus orbis ipsa perfruitur, licet in diversas prolationes et vocabula sit divisa; tum quia naturalis est nobis, cum illa potius artificialis existat. [Of these two kinds of languages, the more noble is the vernacular: first, because it was the language originally used by the human race; second, because the whole world employs it, though with different pronunciations and using different words; and third because it is natural to us, while the other is, in contrast, artificial.)