Link shouldn't talk, but everyone else aside from him should. However, the only way to do this would be to offer no option to change your name from anything other than Link, and I don't expect Aonuma or Miyamoto to ever go through with that solely because its a step away from Link being connected to the player. Its still possible they may someday, or perhaps even in Zelda Wii, but I wouldn't get my hopes up. Still, if they want to give the best realistic experience in Zelda one day, they have no choice but to do this at some point. Voices aid realistic experiences. Not that I expect them to, however. They'll never do it even if they realize it would help, because it strays too far from what they think Zelda should be.