I believe James Earl Jones still stutters. He rarely does media, interviews, talk shows etc. Check out his speech at the AFI awards. You can see and hear some blocks and hesitations. https://youtu.be/4QTwPC3AgU4 However it does not stop him from being an absolute BOSS! Check out his stage acting work. This scene from Fences gives me the chills. https://youtu.be/K_kGtQmvrVI