I don't play WoW anymore, but when I did I played it with the normal English version.
WoW isn't even available in swedish and even if it was I wouldn't use it.
Everything on my computer is in English. OS, programs, everything.
My phone is also in English.
I just prefer English for everything even slightly concerning computer technology. Stuff just turns weird when trying to translate it + it takes extra time. I'm fluent in English anyway so it doesn't matter what language stuff is in.