No voice sound

This one has me….
Lately my Dell XPS has decided to selectively quit playing voices. One instance is my game Mass Effect. All the sounds of the game play normally except for the character voices. It’s weird, voices from characters not actually in the game are heard, gun fire is heard, background music is good. But when the characters speak, they’re muted so low so as to be not understandable. My Dell has also decided certain movies don’t deserve voice sounds but all other sounds come through, put in another movie and everything is fine. This is definitely above my pay grade!