U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES ∙ National Institutes of Health

NIDCD Fact Sheet | Voice, Speech, and Language

Apraxia of Speech 

What is apraxia of speech?

Apraxia of speech (AOS)—also known as acquired apraxia 

of speech, verbal apraxia, or childhood apraxia of speech 

(CAS) when diagnosed in children—is a speech sound 

disorder. Someone with AOS has trouble saying what 

he or she wants to say correctly and consistently. AOS is 

a neurological disorder that affects the brain pathways 

involved in planning the sequence of movements involved 

in producing speech. The brain knows what it wants to 

say, but cannot properly plan and sequence the required 

speech sound movements. 

AOS is not caused by weakness or paralysis of the 

speech muscles (the muscles of the jaw, tongue, or lips). 

Weakness or paralysis of the speech muscles results in 

a separate speech disorder, known as dysarthria. Some 

people have both dysarthria and AOS, which can make 

diagnosis of the two conditions more difficult.

The severity of AOS varies from person to person. It 

can be so mild that it causes trouble with only a few 

speech sounds or with pronunciation of words that 

have many syllables. In the most severe cases, someone 

with AOS might not be able to communicate effectively 

by speaking, and may need the help of alternative 

communication methods.

What are the types and causes of 

apraxia of speech?

There are two main types of AOS: acquired apraxia of 

speech and childhood apraxia of speech.

} Acquired AOS can affect someone at any age, 

although it most typically occurs in adults. Acquired AOS 

is caused by damage to the parts of the brain that are 

involved in speaking and involves the loss or impairment 

of existing speech abilities. It may result from a stroke, 

head injury, tumor, or other illness affecting the brain. 

Acquired AOS may occur together with other conditions 

that are caused by damage to the nervous system. One 

of these is dysarthria, as mentioned earlier. Another 

NIDCD...Improving the lives of people with communication disorders
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is aphasia, which is a language disorder. (For more 

information, see the NIDCD fact sheet “Aphasia” at 

https://www.nidcd.nih.gov/health/aphasia.) 

} Childhood AOS is present from birth. This condition 

is also known as developmental apraxia of speech, 

developmental verbal apraxia, or articulatory apraxia. 

Childhood AOS is not the same as developmental delays 

in speech, in which a child follows the typical path of 

speech development but does so more slowly than 

is typical. The causes of childhood AOS are not well 

understood. Imaging and other studies have not been 

able to find evidence of brain damage or differences in 

the brain structure of children with AOS. Children with 

AOS often have family members who have a history 

of a communication disorder or a learning disability. 

This observation and recent research findings suggest 

that genetic factors may play a role in the disorder. 

Childhood AOS appears to affect more boys than girls.

What are the symptoms of apraxia 

of speech?

People with either form of AOS may have a number of 

different speech characteristics, or symptoms: 

} Distorting sounds. People with AOS may have difficulty 

pronouncing words correctly. Sounds, especially vowels, 

are often distorted. Because the speaker may not place 

the speech structures (e.g., tongue, jaw) quite in the 

right place, the sound comes out wrong. Longer or 

more complex words are usually harder to say than 

shorter or simpler words. Sound substitutions might 

also occur when AOS is accompanied by aphasia. 

} Making inconsistent errors in speech. For example, 

someone with AOS may say a difficult word correctly 

but then have trouble repeating it, or may be able to 

say a particular sound one day and have trouble with 

the same sound the next day. 

} Groping for sounds. People with AOS often appear to 

be groping for the right sound or word, and may try 

saying a word several times before they say it correctly. 

} Making errors in tone, stress, or rhythm. Another 

common characteristic of AOS is the incorrect use 

of prosody. Prosody is the rhythm and inflection of 

speech that we use to help express meaning. Someone 

who has trouble with prosody might use equal stress, 

segment syllables in a word, omit syllables in words and 

phrases, or pause inappropriately while speaking. 

Children with AOS generally understand language much 

better than they are able to use it. Some children with the 

disorder may also have other speech problems, expressive 

language problems, or motor-skill problems.

How is apraxia of speech diagnosed?

Professionals known as speech-language pathologists play 

a key role in diagnosing and treating AOS. Because there 

is no single symptom or test that can be used to diagnose 

AOS, the person making the diagnosis generally looks for 

the presence of several of a group of symptoms, including 

those described earlier. Ruling out other conditions, such 

as muscle weakness or language production problems 

(e.g., aphasia), can help with the diagnostic process.

People with either form 

of AOS may have a 

number of different 

speech characteristics, 

or symptoms, such as 

distorting sounds, making 

inconsistent errors in 

speech, groping for sounds, 

or making errors in tone, 

stress, or rhythm.
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In formal testing for both acquired and childhood AOS, 

a speech-language pathologist may ask the patient to 

perform speech tasks such as repeating a particular word 

several times or repeating a list of words of increasing 

length (for example, love, loving, lovingly). For acquired 

AOS, a speech-language pathologist may also examine 

the patient’s ability to converse, read, write, and perform 

nonspeech movements. To diagnose childhood AOS, 

parents and professionals may need to observe a child’s 

speech over a period of time. 

How is apraxia of speech treated?

In some cases, people with acquired AOS recover some 

or all of their speech abilities on their own. This is called 

spontaneous recovery. 

Children with AOS will not outgrow the problem on their 

own. They also do not acquire the basics of speech just 

by being around other children, such as in a classroom. 

Therefore, speech-language therapy is necessary for 

children with AOS as well as for people with acquired 

AOS who do not spontaneously recover all of their 

speech abilities.

Speech-language pathologists use different approaches 

to treat AOS, and no single approach has been proven to 

be the most effective. Therapy is tailored to the individual 

and is designed to treat other speech or language 

problems that may occur together with AOS. Frequent, 

intensive, one-on-one speech-language therapy sessions 

are needed for both children and adults with AOS. (The 

repetitive exercises and personal attention needed to 

improve AOS are difficult to deliver in group therapy.) 

Children with severe AOS may need intensive speechlanguage therapy for years, in parallel with normal 

schooling, to obtain adequate speech abilities.

In severe cases, adults and children with AOS may need 

to find other ways to express themselves. These might 

include formal or informal sign language; a notebook 

with pictures or written words that can be pointed to and 

shown to other people; or an electronic communication 

device—such as a smartphone, tablet, or laptop 

computer—that can be used to write or produce speech. 

Such assistive communication methods can also help 

children with AOS learn to read and better understand 

spoken language by stimulating areas of the brain 

involved in language and literacy.

Some adults and children will make more progress during 

treatment than others. Support and encouragement from 

family members and friends and extra practice in the 

home environment are important.

What research is being done to better 

understand apraxia of speech?

Researchers are searching for the causes of childhood 

AOS, including the possible role of abnormalities in the 

brain or other parts of the nervous system. They are 

also looking for genetic factors that may play a role in 

childhood AOS. Other research on childhood AOS aims 

to identify more specific criteria and new techniques to 

diagnose the disorder and to distinguish it from other 

communication disorders. 

Research on acquired AOS includes studies to pinpoint the 

specific areas of the brain that are involved in the disorder. 

In addition, researchers are studying the effectiveness 

of various treatment approaches for both acquired and 

childhood AOS.

Speech-language therapy 

is necessary for children 

with apraxia of speech as 

well as for people with 

acquired apraxia of speech 

who do not recover all of 

their speech abilities on 

their own.
Where can I find additional 

information about apraxia of speech?

The NIDCD maintains a directory of organizations that 

provide information on the normal and disordered 

processes of hearing, balance, taste, smell, voice, 

speech, and language. Visit the NIDCD website at 

https://www.nidcd.nih.gov/directory to search the 

directory. 

More NIDCD fact sheets on Voice, Speech, 

and Language:

} Aphasia

} Speech and Language Developmental Milestones

} Specific Language Impairment

} Assistive Devices for People with Hearing, Voice, 

Speech, or Language Disorders 

Visit the NIDCD website at https://www.nidcd.nih.gov to 

read, print, or download fact sheets.

For more information, contact us at:

NIDCD Information Clearinghouse

1 Communication Avenue

Bethesda, MD 20892-3456

Toll-free voice: (800) 241-1044

Toll-free TTY: (800) 241-1055

Email: nidcdinfo@nidcd.nih.gov

https://www.nidcd.nih.gov

 Follow the NIDCD on Twitter at @NIDCD

The NIDCD supports and conducts research and 

research training on the normal and disordered 

processes of hearing, balance, taste, smell, voice, 

speech, and language and provides health information, 

based upon scientific discovery, to the public.

Apraxia of Speech

NIH Pub. No. 13-7466

September 2016

NIH...Turning Discovery Into Health®