what causes stuttering?

I see children who stutter at different times in their lives. When they are 2-3 years old, I work with the parents, to try to make the speaking environment calmer in the home, and more relaxed.  When I see a child who is 6-6 I work with the child. At this point he knows he is stuttering, and needs tips to help him reduce the stuttering. I offer explanations, different types of tools that will slow him down, and help him her how he speaks, and of course, working with the family. Older children, who are in the pre teen years, benefit from small group programs, offered in the clinic or hospital setting.  


Roughly three million Americans stutter. Stuttering affects people of all ages. It occurs most often in children between the ages of 2 and 5 as they are developing their language skills. Approximately 5 percent of all children will stutter for some period in their life, lasting from a few weeks to several years. Boys are twice as likely to stutter as girls; as they get older, however, the number of boys who continue to stutter is three to four times larger than the number of girls. Most children outgrow stuttering. About 1 percent or less of adults stutter.


How is speech normally produced?



What causes stuttering?

Although the precise mechanisms are not understood, there are two types of stuttering that are more common. (A third type of stuttering, called psychogenic stuttering, can be caused by emotional trauma or problems with thought or reasoning. At one time, all stuttering was believed to be psychogenic, but today we know that psychogenic stuttering is rare.)



How is stuttering treated?



For very young children, early treatment may prevent developmental stuttering from becoming a lifelong problem. Certain strategies can help children learn to improve their speech fluency while developing positive attitudes toward communication. Health professionals generally recommend that a child be evaluated if he or she has stuttered for three to six months, exhibits struggle behaviors associated with stuttering, or has a family history of stuttering or related communication disorders. Some researchers recommend that a child be evaluated every three months to determine if the stuttering is increasing or decreasing. Treatment often involves teaching parents about ways to support their child’s production of fluent speech. Parents may be encouraged to:



  • Refrain from reacting negatively when the child stutters. Instead, parents should react to the stuttering as they would any other difficulty the child may experience in life. This may involve gentle corrections of the child’s stuttering and praise for the child’s fluent speech.

  • Be less demanding on the child to speak in a certain way or to perform verbally for people, particularly if the child experiences difficulty during periods of high pressure.





Stuttering therapy

Many of the current therapies for teens and adults who stutter focus on learning ways to minimize stuttering when they speak, such as by speaking more slowly, regulating their breathing, or gradually progressing from single-syllable responses to longer words and more complex sentences. Most of these therapies also help address the anxiety a person who stutters may feel in certain speaking situations.


Drug therapy

The U.S. Food and Drug Administration (FDA) has not approved any drug for the treatment of stuttering. However, some drugs that are approved to treat other health problems—such as epilepsy, anxiety, or depression—have been used to treat stuttering. These drugs often have side effects that make them difficult to use over a long period of time. In a recent study funded by the National Institute on Deafness and Other Communication Disorders (NIDCD), researchers concluded that drug therapy has been largely ineffective in controlling stuttering. Clinical trials of other possible drug treatments are currently under way.


Electronic devices

Some people who stutter use electronic devices to help control fluency. For example, one type of device fits into the ear canal, much like a hearing aid, and digitally replays a slightly altered version of the wearer’s voice into the ear so that it sounds as if he or she is speaking in unison with another person. In some people, electronic devices help improve fluency in a relatively short period of time. Nevertheless, questions remain about how long such effects may last and whether people are able to easily use these devices in real-world situations. For these reasons, researchers are continuing to study the long-term effectiveness of these devices.


Self-help groups



What research is being conducted on stuttering?

Researchers around the world are exploring ways to improve the early identification and treatment of stuttering and to identify its causes. For example, scientists have been working to identify the possible genes responsible for the types of stuttering that tend to run in families. NIDCD scientists have identified three such genes—one on chromosome 12 and two on chromosome 16—that are the source of stuttering in some study participants in Pakistan, England, and the United States. The three genes, called GNPTAB, GNPTG, and NAGPA, work together to help in the breakdown and recycling of cellular components. Interestingly, other mutations in GNPTAB and GNPTG are tied to two serious metabolic disorders, called mucolipidosis (ML) II and III, which are also caused by problems with cellular recycling. Researchers are now studying how this defect in the recycling of cell components leads to specific deficits in speech fluency.




Scientists are using brain imaging tools such as PET (positron emission tomography) and functional MRI (magnetic resonance imaging) scans to investigate brain activity in people who stutter. NIDCD-funded researchers also are looking at brain imaging as a way to help treat people who stutter. Researchers are studying whether volunteer patients who stutter can learn to recognize, with the help of a computer program, specific speech patterns that are linked to stuttering and to avoid using those patterns when speaking.


Where can I get more information?

NIDCD maintains a directory of organizations that can answer questions and provide printed or electronic information on stuttering. Please see the list of organizations atwww.nidcd.nih.gov/directory.


Use the following keywords to help you search for organizations that are relevant to stuttering:

  • Stuttering

  • Speech-language pathologists

  • Physician/practitioner referrals