It is not well known, but the mother tongue of John Calvin was not French—which he learned later in life—but Picard, a Romance language still spoken today that is close to but distinct from French, for he was born in Noyon, Picardy, in north-eastern France.[1]
[1] Bruce Gordon, Calvin (New Haven: Yale University Press, 2009), 4. For an overview of Picard, see “Picard language” (http://en.wikipedia.org/wiki/Picard_language; accessed July 4, 2009).