I liked Biran and Yenke's "bad" singing.

But I'm also guessing the "Ronso choir" sounded like they had years of practice because they actually did. If I had to guess, I would guess it was customary of the Ronso to greet summoners in such a way that had actually made it to Gagazet. They probably didn't get to put it to use much, but I'm still guessing they practiced at it nonetheless.