"(Apologies to those who've had to wear leiderhausen or cowboy hats for the sake of a lucrative gig ... ) "

Leiderhausen - does that mean "to play havoc, unfortunately"? Seems appropriate.

Seriously though, if you learn a vocal technique for a particular genre, very often the accent comes with it, no doubt because of the mouth position you have to adopt, for the same reason that although I have difficulty pronouncing THs in English, I don't have the same problem in Welsh, which I learnt much later in life.