Gallo is a regional language of France. It is not as commonly spoken as it once was, as the standard form of French now predominates. Gallo is classified as one of the Oïl languages.Gallo was originally spoken in the Marches of Neustria, which now corresponds to the border lands of Brittany and Normandy and its former heart in Le Mans, Maine. Gallo was the shared spoken language of the leaders of the Norman conquest of England, most of whom originated in Upper Brittany and Lower Normandy.