Stage and screen actor James Earl Jones is widely known as the voice of film icons Darth Vader (Star Wars) and Mufasa (The Lion King). However, for 10 years in his childhood, that now-legendary voice was not heard by anyone at all.
From the ages of 5 to 14, Jones refused to speak due to his severe stutter. A high school English teacher encouraged him to finally take up speaking again. And of course, it was his voice and speech that carried him to the illustrious career that he enjoys today.
Here is a recent CNN interview with James Earl Jones where he addresses his childhood stuttering and looks back on his career (he talks about his childhood stuttering at 2:47 in the embedded video below).