People who stutter know what they want to say, but have trouble expressing it fluently. Stuttering is a speech disorder that disrupts the flow of speech with repeated sounds, syllables, and words; prolonged sounds; and blocks (interruptions in speech). Some children also have eye blinks, breaks in eye contact, and tension in their lips, tongue, and jaw, when they stutter.
Some children stutter as they’re learning language skills. Most children outgrow stuttering, however, in about 1 percent of people, stuttering persists into adulthood (persistent stuttering).