Everyone in the Bach family was steeped in a vernacular that included dances from all over Europe, courts and countryside. It would not have been possible for anyone to mistake a minuet for a sarabande or courante, or a gavotte for a bourée. It is remarkable that his two of his most musically prominent sons went in completely different directions: C.P.E., whose startling pitch coloration (Empfindsamkeit) prefigure 19th-century chromaticism within pre-Classical structures; W.F., bringing new levels of tone and rhythm abstraction to familiar Baroque structures.
About the closest I have ever found myself to contemporary music that speaks directly to the vernacular is Francis Poulenc. He grasped the fine points of popular genres as of the complex acoustics of the instruments for which he wrote, most especially his own, the piano.
We have just come through a time of great self-consciousness about classical composition. It may be that because Poulenc addressed the vernacular so deeply that his music is undervalued at this time. I suspect that he will be remembered as one of the foremost commentators on and elaborators of our vernacular, both instrumental and vocal, sacred as well as secular.
(Program note to my performance this week.)