I think a lot of the allegedly "recovered" ones are also very good at compensating/hiding/being covert/etc. This [James Earl Jones mini-documentary](http://www.pbs.org/newshour/bb/james-earl-jones-returns-broadway/) is all about how he "overcame" stuttering...and he's clearly switching words throughout the interview (which no one except a stuttering-knowledgeable person would catch).