It is obvious, on the most cursory view of the French and Spanish languages, that they, as well as the Italian, are derived from one common source, the Latin. That must therefore have been at some period, and certainly not since the establishment of the barbarous nations in Spain and Gaul, substituted in ordinary use for the original dialects of those countries which are generally supposed to have been Celtic, not essentially differing from those which are spoken in Wales and Ireland. Rome, says Augustin, imposed not only her yoke, but her language, upon conquered nations. The success of such an attempt is indeed very remarkable. Though it is the natural effect of conquest, or even of commercial intercourse, to ingraft fresh words and foreign idioms on the stock of the original language, yet the entire disuse of the latter, and adoption of one radically different, scarcely takes place in the lapse of a far longer period than that of the Roman dominion in Gaul. Thus, in part of Britany the people speak a language which has perhaps sustained no essential alteration from the revolution of two thousand years; and we know how steadily another Celtic dialect has kept its ground in Wales, notwithstanding English, laws and government, and the long line of contiguous frontier which brings the natives of that principality into contact with Englishmen. Nor did the Romans ever establish their language (I know not whether they wished to do so) in this island, as we perceive by that stubborn British tongue which has survived two conquests.[482] In Gaul and in Spain, however, they did succeed, as the present state of the French and peninsular languages renders undeniable, though by gradual changes, and not, as the Benedictine authors of the Histoire Littéraire de la France seem to imagine, by a sudden and arbitrary innovation.[483] This is neither possible in itself, nor agreeable to the testimony of Irenæus, bishop of Lyons at the end of the second century, who laments the necessity of learning Celtic.[484] But although the inhabitants of these provinces came at length to make use of Latin so completely as their mother tongue that few vestiges of their original Celtic could perhaps be discovered in their common speech, it does not follow that they spoke with the pure pronunciation of Italians, far less with that conformity to the written sounds which we assume to be essential to the expression of Latin words. [Sidenote: Ancient Latin pronunciation.]