Stuttering is a disorder that causes a person to hesitate when speaking, repeat words or sounds, or experience abnormal stoppages of no sound when forming verbal thoughts and sentences. It is a form of dysfluency, which is an interruption in a person’s speech flow.

During normal speech, a person forms a thought that is then coded by the brain into language. The brain then sends signals to the muscles that control speech so that they move in a fashion that produces certain words. The mouth, face, neck, tongue and throat muscles all work in tandem to deliver the words that people hear.

A person who stutters experiences a breakdown in this flow of speech that is known as dysfluency. This happens to everyone occasionally. However, a person who stutters regularly experiences dysfluency that interferes with the ability to communicate.

For most people, stuttering begins in childhood. It is normal for children to stutter between the ages of 2 and 5 years, with the first signs of this obstacle to speech typically appearing between 18 months and 24 months. Children generally stutter when learning new ways to use language, and their stuttering may come and go with each new level of language achievement. This normal, temporary stuttering is sometimes referred to as developmental dysfluency or pseudostuttering. Parents should remain patient with their child during this stage of development, which usually lasts for weeks or months.

After that time, the child will likely progress to more natural speech patterns as basic conversation skills and the ability to coordinate muscles used to talk progress. Once children enter school and begin conversing regularly, stuttering problems tend to drop sharply.

However, in some cases stuttering remains or even worsens as a child grows older. About 20 percent of children develop a stuttering problem that is significant enough to cause parental concern, according to the Stuttering Foundation. Some people only stutter under certain circumstances (such as when speaking before a large group) whereas others may find that stuttering hinders most of their attempts to communicate. About 1 percent of adults stutter, according to the National Institutes of Health.

Certain situations – especially conditions of great stress or embarrassment – can trigger episodes of stuttering.

Research also indicates that children who stutter experience greater difficulty controlling their attention, behavior and emotions than those who do not.