Okay, well, OBVIOUSLY it would have to be COMPLETELY OPTIONAL, because to have that as the only option to select moves is crazy.
But I'd like to think that calling out a pokemon's attack and have it listen is like a childhood dream come true haha :'D
However, the DS's mic is ehhhh, pretty dodgy for reading sound imo, so I doubt we'd get anything like this feature for a real long time :x
But damn, I'd feel badass telling my Ho-oh to use sacred fire ahhhh <3