What is stuttering?

Who stutters?

How is speech normally produced?

Stuttering is a speech disorder in which sounds, 

syllables, or words are repeated or prolonged, 

disrupting the normal flow of speech. These speech 

disruptions may be accompanied by struggling 

behaviors, such as rapid eye blinks or tremors of the 

lips. Stuttering can make it difficult to communicate 

with other people, which often affects a person’s 

quality of life.

Symptoms of stuttering can vary significantly 

throughout a person’s day. In general, speaking 

before a group or talking on the telephone may make 

a person’s stuttering more severe, while singing, 

reading, or speaking in unison may temporarily 

reduce stuttering. 

Stuttering is sometimes referred to as stammering and 

by a broader term, disfluent speech.

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.

We make speech sounds through a series of precisely 

coordinated muscle movements involving breathing, 

phonation (voice production), and articulation 

(movement of the throat, palate, tongue, and lips) 

(see figure). Muscle movements are controlled by the 

brain and monitored through our senses of hearing 

and touch.

Structures involved in speech and 

voice production

NIDCD Fact Sheet

Stuttering 

U.S. DEPARTMENT OF HEALTH & HUMAN SERVICES ∙ NATIONAL INSTITUTES OF HEALTH ∙ NATIONAL INSTITUTE ON DEAFNESS AND OTHER COMMUNICATION DISORDERS voice, speech, language language
How is stuttering diagnosed?

How is stuttering treated?

What causes stuttering?

Stuttering is usually diagnosed by a speech-language 

pathologist (SLP), a health professional who is trained 

to test and treat individuals with voice, speech, and 

language disorders. The speech-language pathologist 

will consider a variety of factors, including the child’s 

case history (such as when the stuttering was first 

Although there is currently no cure for stuttering, there 

are a variety of treatments available. The nature of 

the treatment will differ, based upon a person’s age, 

communication goals, and other factors. If you or your 

child stutters, it is important to work with a speechlanguage pathologist to determine the best treatment 

options.

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:

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.) 

Developmental stuttering

Developmental stuttering occurs in young children 

while they are still learning speech and language 

skills. It is the most common form of stuttering. Some 

scientists and clinicians believe that developmental 

stuttering occurs when children’s speech and language 

abilities are unable to meet the child’s verbal demands. 

Developmental stuttering also runs in families. In 2010, 

for the first time, NIDCD researchers isolated three 

genes that cause stuttering. More information on the 

genetics of stuttering can be found in the research 

section of this fact sheet.

Neurogenic stuttering

Neurogenic stuttering may occur after a stroke, head 

trauma, or other type of brain injury. With neurogenic 

stuttering, the brain has difficulty coordinating the 

different components involved in speaking because 

of signaling problems between the brain and nerves 

or muscles.

noticed and under what circumstances), an analysis 

of the child’s stuttering behaviors, and an evaluation 

of the child’s speech and language abilities and the 

impact of stuttering on his or her life.

When evaluating a young child for stuttering, a 

speech-language pathologist will try to predict if the 

child is likely to continue his or her stuttering behavior 

or outgrow it. To determine this difference, the speechlanguage pathologist will consider such factors as 

the family’s history of stuttering, whether the child’s 

stuttering has lasted six months or longer, and whether 

the child exhibits other speech or language problems.

NIDCD Fact Sheet

Stuttering

voice, speechlanguage
•	 Provide a relaxed home environment that allows 

many opportunities for the child to speak. This 

includes setting aside time to talk to one another, 

especially when the child is excited and has a lot 

to say.

•	 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.

•	 Speak in a slightly slowed and relaxed manner. 

This can help reduce time pressures the child may 

be experiencing. 

•	 Listen attentively when the child speaks and wait 

for him or her to say the intended word. Don’t 

try to complete the child’s sentences. Also, help 

the child learn that a person can communicate 

successfully even when stuttering occurs.

•	 Talk openly and honestly to the child about 

stuttering if he or she brings up the subject. Let 

the child know that it is okay for some disruptions 

to occur.

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 underway.

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

Many people find that they achieve their greatest 

success through a combination of self-study and 

therapy. Self-help groups provide a way for people 

who stutter to find resources and support as they face 

the challenges of stuttering.

more
What research is being conducted Where can I find additional information? on stuttering?

The NIDCD maintains a directory of organizations 

that provide information on the normal and 

disordered processes of hearing, balance, smell, taste, 

voice, speech, and language. Please see the list of 

organizations at http://www.nidcd.nih.gov/directory.

Use the following keywords to help you search for 

organizations that can answer questions and provide 

printed or electronic information on stuttering:

•	 Stuttering

•	 Speech-language pathologists

For more information, additional addresses and phone 

numbers, or a printed list of organizations, contact:

NIDCD Information Clearinghouse

1 Communication Avenue 

Bethesda, MD 20892-3456

Toll-free Voice: (800) 241-1044

Toll-free TTY: (800) 241-1055

E-mail: nidcdinfo@nidcd.nih.gov

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.

Researchers are working to help speech-language 

pathologists determine which children are most likely to 

outgrow their stuttering and which children are at risk 

for continuing to stutter into adulthood. In addition, 

researchers are examining ways to identify groups of 

individuals who exhibit similar stuttering patterns and 

behaviors that may be associated with a common cause.

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. 

NIDCD supports and conducts research and research training on the 

normal and disordered processes of hearing, balance, smell, taste, 

voice, speech, and language and provides health information, based 

upon scientific discovery, to the public.

voice, speech, languagehearing, balancesmell, taste

NIDCD Fact Sheet: Stuttering

Publication No. 10-4232

Updated March 2010

For more information, contact:

NIDCD Information Clearinghouse

1 Communication Avenue

Bethesda, MD 20892-3456

Toll-free Voice: (800) 241-1044

Toll-free TTY: (800) 241-1055

Fax: (301) 770-8977

E-mail: nidcdinfo@nidcd.nih.gov

Internet: http://www.nidcd.nih.gov

The NIDCD Information Clearinghouse is a service of the 

National Institute on Deafness and Other Communication 

Disorders, National Institutes of Health, U.S. Department 

of Health and Human Services.