Fair enough...can the stodgy grouchy types like me get the concession of a counter that tracks how often you restart, and NPCs going "Dammit, do you want to talk or not?! This is the 12th time you've asked me the same question!!" just for giggles?
Lol that would be funny, but yeah a really simple solution to this problem would simply be to have the character halt the conversation and continue, for example:
"blah de blah de blah... Wait I think I hear someone coming.", or " ...Hold on what's that!"
Then after the problems been dealt with, to simply begin the conversation again from the beginning of the interrupted sentence, with an:
"As I was saying ..."
This would definitely add to immersion as it would make conversations seem more natural as well, in spite of merely being a linguistic trick, and it would also be relatively easy to implement as its not difficult to program in due to naturally pauses in language between sentences.