I'm seeing (hearing?) this too. I had the same issue with the new Star Wars game, it was an issue with surround sound and my headphones not playing nice. I don't see an easy way to change sound settings in the options, going to do some digging to see if I can switch to stereo sound in game.
You are the man. I changed my sound settings outside the game so that I am not configured for surround sound and instead using stereo. It sucks losing surround sound but character dialogues are now present and that is HUGE. For a workaround, nice trade off. Thanks - good insight.