The problem you described is often linked to the game outputing in surround sound while you only have stereo speakers. In a surround setup, voices come out of the central speaker, which a stereo setup lacks. The stereo speakers only output the echoes of voices, which is especially bad in conversation cutscenes due to fixed positional audio.
The solution to this problem depends on whether you're playing on a console or PC. If you're on PC, right click the speaker icon in the bottom-right corner, click playback devices, highlight the active playback device, and click on configure. Make sure it's set to stereo. I don't know what this looks like on consoles, but there must be audio settings somewhere.