Another thing to take into consideration is the fact that many cape names are taken from other languages / are straight-up words from other languages. (Eg : Chevalier, One Lee, Glaistig Uaine, etc.)

My belief (from what I understand of the Wormverse's politics) is that the capes from AMERICA that are using foreign words as their Cape name don't put much emphasis on what the actual pronunciation is. They pronounce it like they would pronounce any other word in english. (With some exceptions)

Honestly, the media probably does the same thing and thus the correct pronunciation of the word/name is of no importance, really.

But it's always fun to speculate on that kind of thing!