palilalia, copropraxia
Wikipedia says that "palilalia" is "the repetition or echoing of one's own spoken words."
It can sometimes be a symptom of Tourette Syndrome. I already knew that coprolalia (involuntary swearing) was another such symptom, but I hadn't previously heard the name for yet another symptom: "copropraxia," "involuntarily performing obscene or forbidden gestures."
I normally don't list words here whose meaning is obvious from the roots (when I know the roots); I could've guessed what copropraxia is. But I like the word, so I figured I'd include it.