Those who take part are confronting what is, for many, a palpable fear of public speaking.
"It always provides emotional breakthroughs for participants," said Jim McClure, 53, a Chicago public relations consultant who is a board member of the National Stuttering Project and leader of three Chicago-area NSP groups. "It is big stuff for the speakers."
When he was a child, McClure was told he would grow out of his stuttering. By age 30, he said, "I figured that wasn't going to be the case." McClure then sought out speech therapists who helped him slow down his speaking rate and understand how to take a more gentle approach to some sounds while prolonging others.
"I speak fluently most of the time," he said last week before heading to Buffalo. "I am still a person who stutters; whatever vulnerability caused me to stutter at a young age is still there."
McClure's self-acceptance is a key principle of the National Stuttering Project.
Scott Yaruss, an assistant professor of speech and language pathology and director of stuttering programs at Northwestern University, said many patients eliminate a significant measure of stuttering simply by feeling more comfortable with their condition.
"It helps people to learn muscle-relaxation techniques that can make a big difference," said Yaruss.
Yaruss said the biggest challenge for many is overcoming the misconception that stuttering is some sort of emotional or nervous disorder.
"Stuttering has emotional consequences," said Yaruss, "which is a point of treatment when a psychotherapist can be valuable. But we are doing no one any favors by thinking psychotherapy alone can do the job."
There is no single cause of stuttering, and there are various ways it can prevent a person from speaking fluently. While repeating syllables is a common one, some individuals, such as McClure, experience silent blocks when no sounds come out. There might be other physical symptoms, such as eye rolling, blinking or head jerks.
Speech therapists use different approaches, but there is a consensus that too many parents, teachers and pediatricians take children's stuttering lightly. The U.S. Department of Health and Human Services estimates that about one of 30 children stutters. And although the National Stuttering Project reports that about 25 percent of the children could end up with a chronic problem.
"I heard all of the usual advice as a kid growing up in Wilmette," said John Stossel, an ABC News correspondent who regularly contributes to "20/20" and plays host to four specials each year. "People would tell me to slow down, take a deep breath, that my mind was faster than my mouth."
The misplaced reassurance didn't help. Stossel, who is a celebrity spokesman for the Stuttering Foundation of America, finally managed his stuttering by attending a workshop at the Communications Reconstruction Center in Roanoke, Va.
"It was the most boring and tedious three weeks of my life," recalled Stossel. "We basically started over. We talked at two seconds per syllable."
"I still occasionally have to do a second take with Barbara," Stossel said of "20/20" colleague Barbara Walters. "But I am less self-conscious about it."
Other notable stutterers from whom to draw inspiration: Winston Churchill, Aristotle, Marilyn Monroe, Isaac Newton, actor James Earl Jones, country singer Mel Tillis and opera singer Robert Merrill. Stossel himself did a news segment a few years ago on the success story of ex-Bulls star Bob Love, who is community relations director for the team.
"You definitely want to avoid anyone who says they have the only cure for stuttering," said Stossel. "What works for me might not work for you. People need to find their own way."
For more information about stuttering advice and therapies, call the National Stuttering Project 800-364-1677, Stuttering Foundation of America 800-992-9392 or American Speech-Hearing-Language Association 800-638-8255. PHOTOS: Some notable stutterers: ABC News correspondent John Stossel (left), Winston Churchill, Marilyn Monroe and James Earl Jones (above). Keywords: MEETING ISSUE LANGUAGE BEHAVIOR