Stuttering affects more people than you might think. Roughly 3 million Americans have this speech disorder that makes speaking smoothly difficult. Scientists are learning about what causes people to stutter, and genes tell a big part of the story.
“People with stuttering know exactly what they want to say. They’re just unable to say it at the rate they would like,” says Dr. Dennis Drayna, an NIH expert on the genetics of communication disorders.
Stuttering often involves speech sounds that are repeated or held for too long—often when starting words or sentences. It affects about 1 in 20 children. Most will outgrow the disorder on their own or with the help of a professional called a speech-language pathologist….