Art is correct. All of the 19th Louisiana's companies were from north-northwest Louisiana...not many Frenchies in those units.
As for the 20th Louisiana supposedly six companies were "German" and four were "Irish." I have found the Germans deserted more than the Irish guys. Now, the 13th Louisiana is a whole new story. There were plenty of Irish and all kinds of guys in this unit..even a woman in Company C, Susan Francis, was a Cantineer(looks as though she joined with her husband). I havent dug into the 13th as much as the 20th as of yet.
Its not scientific and its hard to calcuate the desertion rate of Irish over others in the 13th & 20th Consolidated Louisiana...but I will conquer that feet soon enough.