Urianger uses different language patterns than everyone else, but he doesn't pronounce words differently. Except for Y'shtola's name, for some reason.

Are there any interviews with VAs or directors to confirm that cheapness is the reason why?
Not to my knowledge. But some things are obvious from listening. Go watch the cutscene where Merlwyb is trying to parley with the Kobolds -- when she introduces herself, not only does she pronounce her own name incorrectly (Roegadyn W's should be pronounced as V's) you can actually hear her pause as she realizes she mispronounced it, and then continues on anyway.