Personally I like it when characters in a game are making all sorts of Badass commentary. One of my all time favourite in this regard is Jagged Alliance 2. If you played JA2 you know what i mean 
I think there would be room for some creative work with the voices in FE. But of course this is but my opinion.
If you really hate this guys many variations of YyYyYeEeEeEsSsS, i suppose you could delete the wavs in your equivalent directory.
C:\FallenEnchantress\sfx\OldWizard1