The acclaimed English novelist David Mitchell, whose sixth and most recent novel, "The Bone Clocks," was one of Oprah's picks for 2014, is a stammerer. His semi-autobiographical novel "Black Swan Green" deals with that subject. He and his wife, who live in Ireland, have an autistic son, and they translated into English a book by a young autistic Japanese writer Naoki Higashida called "The Reason I Jump: One Boy's Voice from the Silence of Autism."
In this Paris Review interview with Mitchell, he's been asked if he thinks his own stammer had much to do with his desire to write:
On one hand, yes: it makes sense that a kid who can’t express himself verbally would be driven to express himself on the page instead. On the other hand, no: most writers aren’t stammerers and most stammerers aren’t writers. Perhaps the best answer is that the writer that I am has been shaped by the stammering kid that I was, and that although my stammer didn’t make me write, it did, in part, inform and influence the writer I became. It’s true that stammerers can become more adept at sentence construction. Synonyms aren’t always neatly interchangeable. Sometimes choosing word B over word A requires you to construct a different sentence to house it—and quickly, too, before your listener smells the stammering rat.