Language transmission in France in the course of the 20th century

“French shall be the only language of education”, proclaimed the Ministerial Order of 7 June 1880 laying down the model primary school regulations. “The language of the Republic is French”, recently added article 2 of the Constitution (1992). But do families follow the strictures of state education and institutions? What were the real linguistic practices of the population of France in the last century? Sandwiched between the monopoly of the national language and the spread of English, what has become of French regional dialects, and what is happening to the languages introduced by immigration