C'mon, man! This is easy to explain. Joe has a latent stutter. When he gets a little tongue-tired his brain grabs onto a word similar to the word or phrase that he's trying to say. The word that he substitutes will be one that's easier for him to say because he's pronounced it correctly so many times in the past that it's indelible in his hippocampus. This wasn't deliberate. It's just a gaffe.