During game play I cannot hear the advisers voices when they pop-up on screen. All other sounds are working fine. I have tried a variety of compatibility modes and have ran the installer and game as administrator. I am running the game on Windows 7.

Do the advisers animate? Click "Control-O" and check if "Video Playback" has a check mark. When I clear that setting, advisers become silent. It's separate from background music and effects, which could explain why you still hear other sounds.

Yeah, they are animated. I should also point out that all other sounds cut out while they are supposed to be talking. Oh well, I guess I'll just have to make due without.