Just checked out this game since I just heard about it. I thought the series was pretty much dead, so this is really exciting and awesome. However, I'm having a pretty odd issue with the ingame voices. It's kind of hard to explain it, but it sounds like it's a combination of stutter and playing at about 25% speed.
I'm running Win 7 64-bit, and using onboard sound (Realtek, I think). I tried updating OpenAl and now have 3 options on the launcher: Realtek and no sound (both of which result in muting) and generic software, which largely works. Music, sound effects, and even briefing voice is fine. It's only the combat chatter (including in the intro cutscene) that is messed up.
This isn't a huge issue as I can simply turn it off and read the log instead, but it does kind of take away from the experience. It'd also be a shame if I can't hear all your great voice acting work- saw some gameplay vids on YouTube and it's pretty well done.
Thank you for your feedback. This is an interesting issue that hasn't been reported before. Please post full system specs here. I think that updating Realtek drivers and/or disabling vsync might help as well.