Patrolling the wasteland makes you wish for a nuclear winter.
I'm no dialogue expert, but I'd wager that the follower phrases have a chance % on them. If so, I suggest moving to a variable instead, like bPlayerGivesADamnWhatISay that they can check.
I tried something like that. I made a single variable in a quest script which was recalculated as a random number between 1 - 99 every 5 seconds. I put conditions in the sorta-annoying lines so that they couldn't get said unless that number had kicked out the 'right' range of random numbers. What it SEEMED to act like (but i'm not sure) was that when a follower wanted to say a line, but couldn't because I'd excluded it by condition, it still counted toward some kind of internal forced-cooldown on chat dialogue. If I had to throw out a wild guess with no hard facts, that would be it. In any case the result was - - the chatty lines that weren't explicitly scripted weren't getting said, by and large. I undid it all shortly after I realized.