Heheh...I haven't heard that. I have had certain followers say some really weird things, though. Apparently if you add them to player faction (tested on Marcurio), they'll start using whisper-shout taunts instead of usual greetings when you walk up to them. "Hey skeever-butt!"

Well, then don't add them to the player faction.
Erik the Slayer's had a few derp moments, such as shouting "Is that all you've got?!" ...at a fire-spewing pressure plate he was standing on, or commenting to me that the cave we were in was a bit dull--apparently failing to notice the werewolf standing not five feet behind him.

Sigh. Moments like that are part of why I keep him around, of course. Free entertainment!
He has yet to refer to my character as "skeever-butt," though. Possibly because he knows she'd turn him into a charbroiled Nord for that.

Never heard "howdy partner" either, from him or from any other NPC in the game.