My French ancestors that I know about were all Huguenots, and many of them sought refuge in Germany and the Netherlands (as did many other Huguenots who left France between the 1580's and 1685), which leads to a whole set of other linguistic changes in spelling and pronunciation (Boudemont becoming "Buttman" or "Putman" in Germany, "Seloivre" becoming "Sloover" or "Slover" in the Netherlands).