He does, just not very often. He responds to questions occasionally (with dialogue options chosen by the player) and says "Come on!" occasionally in The Wind Waker. He just prefers to let his actions speak for him. Or his partner, whoever it might be. Occasionally NPCs will react as if Link has said something, though, even when we don't see him say anything, so it might be that he DOES talk, but we just don't see what he says. He talks all the time in the manga, though.
I'd like to mention he is also a silent protagonist, think Red from Pokemon. He DOES talk, we just never see/hear him talk.
I'd also like to mention that Nintendo HAS had him talk in the past-the dreaded CD-I games and the horrid Zelda cartoon from the 80s-but has failed miserably in the past. Perhaps it's best Link is kept silent. The real problem with Link in the cartoon is that he's an obnoxious pervert who just so happened to save the princess. Yeah. This is why I like the mangas. They have him talk and give him a personality without destroying that respect you have for him.
There's a scene in Twilight Princess where you can clearly see him talking to Ilia. I agree with the comparison to Red from Pokemon. Silent protagonist doesn't mean the protagonist can't talk. Even in Pokemon, there are signs that Red can very much talk. And yeah, the game just flows better keeping him quiet. Unless you want to hear EXCUUUUUUUUUUUUUUUUUUSE ME PRINCESS a hundred times.