Fizzl: My experience of the G35 is all problems are fixed by switching to stereo then back to surround. (Just bellow the power button)
This sorts the can't hear people speak bug for me.
I'm using the latest Logitech drivers.
Since the G35 physically can not receive anything but 7.1 sound, as in it isn't receiving any sound for it to re-mix into stereo to begin with using the Logitech drivers, this is physically impossible.
Your response sounds so similar to the response Logitech customer support has given for the last few years ever since the headset came onto market and gamers found out that any game without 7.1 sound support simply wouldn't work, clearly showing a complete lack of understanding of how their headset works on a physical, hardware, level.
To be clear, Logitech drivers aside, the hardware is fully capable of receiving non 7.1 sound. But, the Logitech drivers ONLY allow it to receive 7.1 sound, from which it can re-mix into stereo using the physical switch on the headset.
Logitech could have ended years of angst years ago by simply modifying their drivers. They haven't, and instead game after game has had to bend over backwards for this one obstinate company.
Edit: And, yes. I own a G35. I'm well aware of how it works. This problem with the Witcher 2 is a problem it's had with many, many games. It's a well known issue since practically the first day the headset appeared.