I caught myself watching an AI video on youtube a few days ago where the narrator's AI voice had deliberate instances of stammering and stuttering. It's definitely simple to have these introduce idiosyncrasies just through specific prompting.
humans often stutter, stammer, uh uh , uhmm, hmmm, to keep the "ball, conch, etc." in thier posession but gain time to complete a response to edge case dialogue. mimickery none the less, but functional, rather than primarily deceptive.