Sounds like a game issueI just did this and there was metered sound with the intro and in game music, but once the beginning narration started with the priest I believe, I could not hear his voice even though the subtitles were playing. The sound and the metering stopped
I'd look into what libraries the game uses. Pretty much it sounds like the game isn't generating the sound. Depending how much you want to get into it you need to research what sound libraries the game uses. OpenAL? Directsound? Are they using a specific wav file format?
I'd probably start by looking if there are any sound related technologies in their disclosures or splash screens, even looking in the game directory for sound related dlls
I don't have the game so can't help you much there
Might even be related to the game just not correctly triggering the dialog sound files, in that case it's a game bug.
One thing to maybe try to see if it a game trigger bug is to try and set the affinity for the game to one CPU. Maybe it's a multi threading issue (the sound thread not triggering at the right time)
I wish you the best of luck