#escapefromdeath

I really do not know, I have given it some thought. There is reason to go both ways. I have heard the argument that if it is Zelda, we will not see her until late in the game because that would mean she would be imprisioned in some fashion, and to that I have to recall A Link to the Past where a similar sort of thing happened and you saw her very early in the game. That being said you did not get to see very much of her after that. However, that voice does not necessarily mean imprisonment; it could be her contacting him through some kind of telepathy to awaken the hero. I mean, it is, but you get my point.

A reason that it may not be Zelda is that usually Zelda is around the same age as Link, and Link looks approximately fifteen to me and that voice sounded older in my opinion. Then again, it is plausible that Zelda could be older than our hero. 

A reason that it could be Zelda is, like I said before, she is contacting him to get up because her kingdom has fallen under chaos and she needs the hero to purify the land and wipe out Ganon. Zelda has played that role in the past before basically. 

Link is waking up in that water, and I read that he was a previous Link ‘asleep’ for a century. (Taking Ocarina of Time to the next level haha.) So that would mean that someone put him there, someone knows he is there, and they are keeping him there for a purpose, that purpose being to rise again when Hyrule needs him. It appears to be the Sheikah technology we have been seeing, so perhaps the one trying to get him up is a Sheikah, or not. It could be Zelda, or it could very well be someone else. 

Whoever is waking him up must know he is there and what his purpose is.