What many thought was stuttering was a prop, not a handicap.
Churchill’s speech problem was a lisp. He could not pronounce the letter “S” and never really learned to do so—so he turned it into a prop, exaggerating words like his famous “Narzzsseess” for “Nazis.”
What some people thought was stuttering was his habit of turning over a word or phrase in an undertone before settling on the final words. He often used this technique in speeches, because he found that it would stir people to renewed interest in what he was about to say next.
Example is a quote from his speech at Harvard University, 6 September 1943:“Man has parted company with his faithful friend the horse, and has sailed into the azure on the wings of eagles—eagles being represented by the infernal….uh, er, ah…..I mean internal combustion engine…..ah….engine.” (Churchill By Himself, 207.) The “ers” and “ahs” don’t usually show up in printed transcripts—but they were there.
But he never stuttered in the medical sense of the term.