"The real breakthrough in my therapy was when I realized, You know what? This is a physiological problem, and there are things I can do to practice and control my fluency," he said.
"And not only that, I'm not crazy," he added.
But according to Yates, that's one of the biggest misconceptions surrounding stuttering.
"There's a tremendous amount of misinformation [about stuttering]," Yates said. "It's not a personality disorder, and people who stutter have normal intelligence, but there's been a lot of misconceptions over the years."
She said because stuttering only affects about two million Americans, it's possible to live a lifetime without crossing paths with someone who stutters.
Since the movie's release, Kershaw said he's noticed more of an interest in stuttering.
"Now people ask me about it," Kershaw said. "They ask me about my own difficulties, and there's been an opening of the door now to talk about it."
For Slack, too, "The King's Speech" had an emotional impact.
"For every 99 hours I spend angry or ashamed or embarrassed about the way I speak, there's at least one hour where I feel proud of it because I know that I wouldn't have the same sensitivity, compassion, or strength of character if I didn't stutter," Slack said. "[Seeing the movie] was one of those hours."
ABCNews.com contributor Danielle Waugh is a member of the ABC News on Campus bureau in Syracuse, N.Y.