In 1790, the Abbé Grégoire sent out a questionnaire asking which languages people spoke [in the French countryside]. The answers he received (at any rate those he could understand) were alarming. Large parts of France "were barely French at all": two hundred and fifty years after the Ordinances of Villers-Cotterêts, which had made the dialect of Paris and the Île-de-France the language of official documents, six million citizens still couldn't speak the national language.
--Michael Sheringham in a review of The Discovery of France, by Graham Robb. Review in the London Review of Books, 31 July 2008