I have a feeling that they overdid the faithfullness to the original tabletop game, because the lingo seems like trying to roleplay coolness to the max. I don't like the lingo, at least not this over the top use of it in every damn conversation.
As for turning off the voice, maybe we will see a mod for that some time after release, but I don't think he devs will do it, considering how much they emphasize the cinematic feel.