There is already voice acting in Zelda, and I love it.
Midna is the most prominent example, and KotRL, Ezlo, and (slightly) ganondorf. Other characters also make grunts and other noises, and that's great.
I however would not like the characters to speak any known language. Their grumblings are perfect, imo. The best example of this is Midna, or WW Ganondorf.








