...or just another Grand Slam melt down. Oh wait, this isn't the French. and here's a previous discussion on maria's vocalizations.
Dr. Bombay: Thank god she lost, I muted the TV so I wouldn't have to listen to her grunts... I am waiting for someone to point out that making sounds that loud takes energy -- energy that is needed if one is going to endure an extra set or a tiebreaker. When Sharapova gets to her third set, note how quieter her grunting is. At the U.S. Open, she was almost silent before finally succumbing, clearly exhausted. I have never seen a baseball player or a golfer or a hockey player grunt while swinging and connecting -- why do tennis players do it? It would make more sense if the aforementioned did the vocalizing, since they only need any perceived "umph" when they are, for a split second, striking the ball or a puck; they aren't doing so while constantly running back and forth and side to side and leaping and lunging non-stop for sixty seconds (or longer) at a time. Maria, if you are reading (fat chance), just try to cool it with the Howard Dean impersonations for just one match, and see if you don't have more energy at the end. If you need something to scream about, I'm sure we could find an activity in which it would be appropriate. Wink wink! Nudge nudge!
Smithee, Andy Roddick might have something to say about that. And I'd guess that the grunt comes from their training. They learn to "talk their way" through the stroke. It helps them to maintain a consistent rhythm through hundreds of hits in a match, even when they're exhausted. It might be a Bollettieri School technique. That's just a guess, though.
Martial artists use vocalisation, I think it's called the 'ky-ai' in karate, for example. Someone out there will know the right terms. It has to do with coordinating breathing to achieve the right focus/power for a punch or kick, according to my spouse, who is a former nationally-ranked karate champ. But its use in other sports? The only time I have heard it on the soccer field was when someone's leg was broken. But that could have just been the excruciating pain.