I have this problem too. When the NPC is staring at me waiting to speak, I found that opening settings and changing any video setting at all, up or down, prompts the conversation to move forward again. For awhile. Then I go back in and have to adjust it again. I basically keep bumping one of the top few graphical settings up and down over the course of a session to keep the conversations moving. It is incredibly bizarre, but not as bizarre as being stared down by an NPC for a minute before they respond to you.
XBox Live PC version here.
EDIT:
Think it is resolved now. Uninstalled the game, installed all windows updates including optionals, and reinstalled the game through xbox live app. No audio pausing now. I'd have replied to this thread instead, but apparently this forum limits you to a handful of posts per day, for whatever stupid reason.