Voice Sound Issues

[CanibalPete]

Not sure if this is a game glitch, or what. I noticed while at a friends house the other day that her game has voice sounds. When she goes to visit Elizabeth Swann, for instance, she actually hears what she's saying, as opposed to just seeing it on the screen. I've never had more than sound effects and music...am I missing something? I tried reinstalling, to see if that was the issue, but had no luck. I've checked my settings, haven't found anything there. We're both on PC's, I'm using XP, she's using Vista. Any ideas?