speech disorder definition

An official website of the United States government

Here’s how you know

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( Lock Locked padlock icon ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

• Health Topics
• Drugs & Supplements
• Medical Tests
• Medical Encyclopedia
• About MedlinePlus
• Customer Support

Speech disorders - children

A speech disorder is a condition in which a person has problems creating or forming the speech sounds needed to communicate with others. This can make the child's speech difficult to understand.

Common speech disorders are:

• Articulation disorders
• Phonological disorders
• Voice disorders or resonance disorders

Speech disorders are different from language disorders in children . Language disorders refer to someone having difficulty with:

• Getting their meaning or message across to others (expressive language)
• Understanding the message coming from others (receptive language)

Speech is one of the main ways in which we communicate with those around us. It develops naturally, along with other signs of normal growth and development . Disorders of speech and language are common in preschool age children.

Disfluencies are disorders in which a person repeats a sound, word, or phrase. Stuttering may be the most serious disfluency. It may be caused by:

• Genetic abnormalities
• Emotional stress
• Any trauma to brain or infection

Articulation and phonological disorders may occur in other family members. Other causes include:

• Problems or changes in the structure or shape of the muscles and bones used to make speech sounds. These changes may include cleft palate and tooth problems.
• Damage to parts of the brain or the nerves (such as from cerebral palsy ) that control how the muscles work together to create speech.
• Hearing loss.

Voice disorders are caused by problems when air passes from the lungs, through the vocal cords, and then through the throat, nose, mouth, and lips. A voice disorder may be due to:

• Acid from the stomach moving upward ( GERD )
• Cancer of the throat
• Cleft palate or other problems with the palate
• Conditions that damage the nerves that supply the muscles of the vocal cords
• Laryngeal webs or clefts (a birth defect in which a thin layer of tissue is between the vocal cords)
• Noncancerous growths (polyps, nodules, cysts, granulomas, papillomas, or ulcers) on the vocal cords
• Overuse of the vocal cords from screaming, constantly clearing the throat, or singing
• Hearing loss

Stuttering is the most common type of disfluency.

Symptoms of disfluency can include:

• Repetition of sounds, words, or parts of words or phrases after age 4 (I want...I want my doll. I...I see you.)
• Putting in (interjecting) extra sounds or words (We went to the...uh...store.)
• Making words longer (I am Boooobbby Jones.)
• Pausing during a sentence or words, often with the lips together
• Tension in the voice or sounds
• Frustration with attempts to communicate
• Head jerking while talking
• Eye blinking while talking
• Embarrassment with speech

ARTICULATION DISORDER

The child is not able to produce speech sounds clearly, such as saying "coo" instead of "school."

• Certain sounds (like "r", "l", or "s") may be consistently distorted or changed (such as making the 's' sound with a whistle).
• Errors may make it hard for people to understand the person (only family members may be able to understand a child).

PHONOLOGICAL DISORDER

The child does not use some or all of the speech sounds to form words as expected for their age.

• The last or first sound of words (most often consonants) may be left out or changed.
• The child may have no problem pronouncing the same sound in other words (a child may say "boo" for "book" and "pi" for "pig", but may have no problem saying "key" or "go").

VOICE DISORDERS

Other speech problems include:

• Hoarseness or raspiness to the voice
• Voice may break in or out
• Pitch of the voice may change suddenly
• Voice may be too loud or too soft
• Person may run out of air during a sentence
• Speech may sound odd because too much air is escaping through the hose (hypernasality) or too little air is coming out through the nose (hyponasality)

Exams and Tests

Your health care provider will ask about your child's developmental and family history. The provider will do some neurological screening and check for:

• Fluency of speech
• Any emotional stress
• Any underlying condition
• Effect of speech disorder on daily life

Some other evaluation tools used to identify and diagnose speech disorders are:

• Denver Articulation Screening Examination.
• Leiter International Performance scale-3.
• Goldman-Fristoe Test of Articulation 3 (GFTA-3).
• Arizona Articulation and Phonology Scale 4th Revision (Arizona-4).
• Prosody-voice screening profile.

A hearing test may also be done to rule out hearing loss as a cause of the speech disorder.

Children may outgrow milder forms of speech disorders. The type of treatment will depend on the severity of the speech disorder and its cause.

Speech therapy may help with more severe symptoms or any speech problems that do not improve.

In therapy, the therapist may teach your child how to use their tongue to create certain sounds.

If a child has a speech disorder, parents are encouraged to:

• Avoid expressing too much concern about the problem, which can actually make matters worse by making the child more self-conscious.
• Avoid stressful social situations whenever possible.
• Listen patiently to the child, make eye contact, don't interrupt, and show love and acceptance. Avoid finishing sentences for them.
• Set aside time for talking.

Support Groups

The following organizations are good resources for information on speech disorder and its treatment:

• American Institute for Stuttering -- stutteringtreatment.org
• American Speech-Language-Hearing Association (ASHA) -- www.asha.org/
• The Stuttering Foundation -- www.stutteringhelp.org
• National Stuttering Association (NSA) -- westutter.org

Outlook (Prognosis)

Outlook depends on the cause of the disorder. Speech can often be improved with speech therapy. Early treatment is likely to have better results.

Possible Complications

Speech disorders may lead to challenges with social interactions due to difficulty communicating.

When to Contact a Medical Professional

Call your provider if:

• Your child's speech is not developing according to normal milestones.
• You think your child is in a high-risk group.
• Your child is showing signs of a speech disorder.

Hearing loss is a risk factor for speech disorders. At-risk infants should be referred to an audiologist for a hearing test. Hearing and speech therapy can then be started, if necessary.

As young children begin to speak, some disfluency is common, and most of the time, it goes away without treatment. If you place too much attention on the disfluency, a stuttering pattern may develop.

Alternative Names

Articulation deficiency; Articulation disorder; Phonological disorder; Voice disorders; Vocal disorders; Disfluency; Communication disorder - speech disorder; Speech disorder - stuttering; Cluttering; Stammering; Childhood onset fluency disorder

American Speech-Language-Hearing Association website. Voice disorders. www.asha.org/Practice-Portal/Clinical-Topics/Voice-Disorders/ . Accessed April 12, 2022.

Simms MD. Language development and communication disorders. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics . 21st ed. Philadelphia, PA: Elsevier; 2020: chap 52.

Trauner DA, Nass RD. Developmental language disorders. In: Swaiman KF, Ashwal S, Ferriero DM, et al, eds. Swaiman's Pediatric Neurology: Principles and Practice . 6th ed. Philadelphia, PA: Elsevier; 2017:chap 53.

Zajac DJ. Evaluation and management of speech disorders for the patient with cleft palate. In: Fonseca RJ, ed. Oral and Maxillofacial Surgery . 3rd ed. St Louis, MO: Elsevier; 2018:chap 32.

Review Date 2/24/2022

Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Related MedlinePlus Health Topics

• Speech and Language Problems in Children

• Bipolar Disorder
• Therapy Center
• When To See a Therapist
• Types of Therapy
• Best Online Therapy
• Best Couples Therapy
• Best Family Therapy
• Managing Stress
• Sleep and Dreaming
• Understanding Emotions
• Self-Improvement
• Healthy Relationships
• Student Resources
• Personality Types
• Verywell Mind Insights
• 2023 Verywell Mind 25
• Mental Health in the Classroom
• Editorial Process
• Meet Our Review Board
• Crisis Support

What Is a Speech Sound Disorder?

Elizabeth is a freelance health and wellness writer. She helps brands craft factual, yet relatable content that resonates with diverse audiences.

Daniel B. Block, MD, is an award-winning, board-certified psychiatrist who operates a private practice in Pennsylvania.

Halfpoint Images / Getty Images

Speech sound disorders are a blanket description for a child’s difficulty in learning, articulating, or using the sounds/sound patterns of their language. These difficulties are usually clear when compared to the communication abilities of children within the same age group.

Speech developmental disorders may indicate challenges with motor speech. Here, a child experiences difficulty moving the muscles necessary for speech production. This child may also face reduced coordination when attempting to speak.

Speech sound disorders are recognized where speech patterns do not correspond with the movements/gestures made when speaking.  

Speech impairments are a common early childhood occurrence—an estimated 2% to 13% of children live with these difficulties. Children with these disorders may struggle with reading and writing. This can interfere with their expected academic performance. Speech sound disorders are often confused with language conditions such as specific language impairment (SLI).

This article will examine the distinguishing features of this disorder. It will also review factors responsible for speech challenges, and the different ways they can manifest. Lastly, we’ll cover different treatment methods that make managing this disorder possible.

Symptoms of Speech Sound Disorder

A speech sound disorder may manifest in different ways. This usually depends on the factors responsible for the challenge, or how extreme it is.

There are different patterns of error that may signal a speech sound disorder. These include:

• Removing a sound from a word
• Including a sound in a word
• Replacing hard to pronounce sounds with an unsuitable alternative
• Difficulty pronouncing the same sound in different words (e.g., "pig" and "kit")
• Repeating sounds or words
• Lengthening words
• Pauses while speaking
• Tension when producing sounds
• Head jerks during speech
• Blinking while speaking
• Shame while speaking
• Changes in voice pitch
• Running out of breath while speaking

It’s important to note that children develop at different rates. This can reflect in the ease and ability to produce sounds. But where children repeatedly make sounds or statements that are difficult to understand, this could indicate a speech disorder.

Diagnosis of Speech Sound Disorders

For a correct diagnosis, a speech-language pathologist can determine whether or not a child has a speech-sound disorder.

This determination may be made in line with the requirements of the DSM-5 diagnostic criteria . These guidelines require that:

• The child experience persistent difficulty with sound production (this affects communication and speech comprehension)
• Symptoms of the disorder appear early during the child’s development stages
• This disorder limits communication. It affects social interactions, academic achievements, and job performance.
• The disorder is not caused by other conditions like a congenital disorder or an acquired condition like hearing loss . Hereditary disorders are, however, exempted. 

Causes of Speech Sound Disorders

There is no known cause of speech sound disorders. However, several risk factors may increase the odds of developing a speech challenge. These include:

• Gender : Male children are more likely to develop a speech sound disorder
• Family history : Children with family members living with speech disorders may acquire a similar challenge.
• Socioeconomics : Being raised in a low socioeconomic environment may contribute to the development of speech and literacy challenges.
• Pre- and post-natal challenges : Difficulties faced during pregnancy such as maternal infections and stressors may worsen the chances of speech disorders in a child. Likewise, delivery complications, premature birth, and low-birth-weight could lead to speech disorders.
• Disabilities : Down syndrome, autism , and other disabilities may be linked to speech-sound disorders.
• Physical challenges : Children with a cleft lip may experience speech sound difficulties.
• Brain damage : These disorders may also be caused by an infection or trauma to a child’s brain . This is seen in conditions like cerebral palsy where the muscles affecting speech are injured.

Types of Speech Sound Disorders

By the time a child turns three, at least half of what they say should be properly understood. By ages four and five, most sounds should be pronounced correctly—although, exceptions may arise when pronouncing “l”, “s”,”r”,”v”, and other similar sounds. By seven or eight, harder sounds should be properly pronounced. 

A child with a speech sound disorder will continue to struggle to pronounce words, even past the expected age. Difficulty with speech patterns may signal one of the following speech sound disorders:

This refers to interruptions while speaking. Stuttering is the most common form of disfluency. It is recognized for recurring breaks in the free flow of speech. After the age of four, a child with disfluency will still repeat words or phrases while speaking. This child may include extra words or sounds when communicating—they may also make words longer by stressing syllables.

This disorder may cause tension while speaking. Other times, head jerking or blinking may be observed with disfluency. 

Children with this disorder often feel frustrated when speaking, it may also cause embarrassment during interactions. 

Articulation Disorder

When a child is unable to properly produce sounds, this may be caused by inexact placement, speed, pressure, or movement from the lips, tongue, or throat.  

This usually signals an articulation disorder, where sounds like “r”, “l”, or “s” may be changed. In these cases, a child’s communication may be understood by only close family members.

Phonological Disorder

A phonological disorder is present where a child is unable to make the speech sounds expected of their age. Here, mistakes may be made when producing sounds. Other times, sounds like consonants may be omitted when speaking.  

Voice Disorder

Where a child is observed to have a raspy voice, this may be an early sign of a voice disorder. Other indicators include voice breaks, a change in pitch, or an excessively loud or soft voice.  

Children that run out of breath while speaking may also live with this disorder. Likewise, children may sound very nasally, or can appear to have inadequate air coming out of their nose if they have a voice disorder.

Childhood apraxia of speech occurs when a child lacks the proper motor skills for sound production. Children with this condition will find it difficult to plan and produce movements in the tongue, lips, jaw, and palate required for speech.  

Treatment of Speech Sound Disorder

Parents of children with speech sound disorders may feel at a loss for the next steps to take. To avoid further strain to the child, it’s important to avoid showing excessive concern.

Instead, listening patiently to their needs, letting them speak without completing their sentences, and showing usual love and care can go a long way.

For professional assistance, a speech-language pathologist can assist with improving a child’s communication. These pathologists will typically use oral motor exercises to enhance speech.

These oral exercises may also include nonspeech oral exercises such as blowing, oral massages and brushing, cheek puffing, whistleblowing, etc.

Nonspeech oral exercises help to strengthen weak mouth muscles, and can help with learning the common ways of communicating.

Parents and children with speech sound disorders may also join support groups for information and assistance with the condition.

A Word From Verywell

It can be frustrating to witness the challenges in communication. But while it's understandable to long for typical communication from a child—the differences caused by speech disorders can be managed with the right care and supervision. Speaking to a speech therapist, and showing love o children with speech disorders can be important first steps in overcoming these conditions.

Eadie P, Morgan A, Ukoumunne OC, Ttofari Eecen K, Wake M, Reilly S. Speech sound disorder at 4 years: prevalence, comorbidities, and predictors in a community cohort of children . Dev Med Child Neurol . 2015;57(6):578-584. doi:10.1111/dmcn.12635

McLeod S, Harrison LJ, McAllister L, McCormack J. Speech sound disorders in a community study of preschool children . Am J Speech Lang Pathol . 2013;22(3):503-522. doi:10.1044/1058-0360(2012/11-0123)

Murphy CF, Pagan-Neves LO, Wertzner HF, Schochat E. Children with speech sound disorder: comparing a non-linguistic auditory approach with a phonological intervention approach to improve phonological skills . Front Psychol . 2015;6:64. Published 2015 Feb 4. doi:10.3389/fpsyg.2015.00064

Penn Medicine. Speech and Language Disorders-Symptoms and Causes .

PsychDB. Speech Sound Disorder (Phonological Disorder) .

Sices L, Taylor HG, Freebairn L, Hansen A, Lewis B. Relationship between speech-sound disorders and early literacy skills in preschool-age children: impact of comorbid language impairment . J Dev Behav Pediatr . 2007;28(6):438-447. doi:10.1097/DBP.0b013e31811ff8ca

American Speech-Language-Hearing Association. Speech Sound Disorders: Articulation and Phonology .

American Speech-Language-Hearing Association. Speech Sound Disorders .

MedlinePlus. Phonological Disorder .

National Institute on Deafness and Other Communication Disorders. Articulation Disorder .

National Institute of Health. Phonological Disorder.

Lee AS, Gibbon FE. Non-speech oral motor treatment for children with developmental speech sound disorders . Cochrane Database Syst Rev . 2015;2015(3):CD009383. Published 2015 Mar 25. doi:10.1002/14651858.CD009383.pub2

By Elizabeth Plumptre Elizabeth is a freelance health and wellness writer. She helps brands craft factual, yet relatable content that resonates with diverse audiences.

Speech Sound Disorder

Reviewed by Psychology Today Staff

Speech sound disorder (SSD) encompasses a group of communication disorders in which children have persistent difficulty articulating words or sounds correctly. Speech sound production requires both the phonological knowledge of speech sounds and the ability to coordinate the jaw, tongue, and lips with breathing and vocalizing to produce meaningful sounds. Children with speech sound disorder may have difficulty with the phonological knowledge of speech sounds or the ability to coordinate the movements necessary for speech. The communication difficulties can impede the development of children by limiting their ability to effectively participate in social, academic, or occupational activities.

While some speech sound disorders stem from physical structural anomalies, such as cleft palate, others have their origin in perceptual problems such as hearing impairment. Still others, like apraxia, in which the brain does not deliver the correct movement instructions to the target muscles, arise from neurodevelopmental problems.

Most children shorten words and syllables as they’re learning to talk, but children with speech sound disorder continue this simplification process past the age when most children can produce words clearly, generally agreed to be age 7.

The DSM-5 includes the following diagnostic criteria for speech sound disorder:

• Persistent difficulty with the production of speech sounds that interferes with the intelligibility of one's speech or prevents verbal communication
• Limitations on communication interfere with social participation or performance at school or work
• The symptoms begin early in life and are not attributable to other medical or neurological conditions

Developmental experts believe that approximately half of a child’s speech is intelligible by age 2 and most speech intelligible by age 4.

According to the Child Mind Institute, other potential signs of a speech sound disorder include:

• Leaving out sounds or substituting an incorrect sound for a correct one
• An unusually hoarse or nasal voice or sudden changes in pitch or loudness that make understanding speech more difficult
• Running out of air while talking

Stuttering is a common example of a speech sound disorder. Another particularly common example is lisping. Depending on the severity of the lisp or stutter, children may attempt to avoid words or phrases with which they struggle due to the anxiety of anticipating their dysfluency.

A speech-language pathologist tests a child's speech for how well he or she creates sounds and inspects how the child moves his or her lips, jaw, and tongue. The pathologist may also test the child’s hearing.

Speech sound disorder is not the same as a specific language impairment. Speech sound disorder expresses itself with a delayed ability to produce speech sounds, while specific language impairment expresses itself with an inability to incorporate the structures of grammar into speech. Only about 2 percent of children with speech sound disorder also have specific language impairment.

According to the National Institute on Deafness and Other Communication Disorders, the prevalence of speech sound disorder in young children is 8 to 9 percent of the population. By first grade, roughly 5 percent of children exhibit speech sound disorder.

The cause of speech sound disorder is not well understood in many cases. Children who develop speech sound disorder often have family members with a history of speech or language disorder, suggesting a genetic component of this condition. Speech sound disorder may occur along with other delays in the use of facial musculature, such as difficulties in chewing, maintaining a closed mouth, and blowing one’s nose

Hearing impairment or deafness do often result in abnormalities of speech sounds. This does not mean someone with a hearing impairment has a neurodevelopmental speech sound disorder. For instance, a child who receives cochlear implants may be able to catch up to peers in speech sound production due to their new ability to hear others better. 

Speech sound disorder is a neurodevelopmental disorder unrelated to anxiety. The disorder could, however, lead to anxiety in children who are unable to fully express themselves. Such anxiety could be expressed as selective mutism , where children do not speak in certain circumstances due to embarrassment .

There is substantial research suggesting the heritability of speech sound disorder. Studies have demonstrated familial aggregation for SSD, where approximately 26 percent of nuclear family members and 13.6 percent of extended family members were affected in a cohort of children with SSD.

Treatment for speech sound disorder primarily consists of speech and language therapy . A speech-language pathologist typically develops a treatment plan that helps a child identify and correct the specific sounds or words they have difficulty articulating. The speech-language pathologist may show the child how to move their tongue and lips to produce sounds correctly and provide opportunities to practice these skills.

In most cases, children with speech sound disorder respond well to speech therapy; speech difficulties improve over time. The condition appears to resolve in 75 percent of children by age 6. When a language disorder is also present, however, speech sound disorder has a poorer prognosis and may be associated with learning disorders.

According to the American Speech-Language-Hearing Association, treatment is generally done with the help of a speech pathologist and focusing on: establishing a target sounds to work on producing reliably, working up from syllables to words to sentences, and, finally, stabilizing this sound production to the point where the patient is able to self-monitor and self-correct.

• Find a Therapist
• Find a Treatment Center
• Find a Psychiatrist
• Find a Support Group
• Find Teletherapy
• United States
• Brooklyn, NY
• Chicago, IL
• Houston, TX
• Los Angeles, CA
• New York, NY
• Portland, OR
• San Diego, CA
• San Francisco, CA
• Seattle, WA
• Washington, DC
• Asperger's
• Bipolar Disorder
• Chronic Pain
• Eating Disorders
• Passive Aggression
• Personality
• Goal Setting
• Positive Psychology
• Stopping Smoking
• Low Sexual Desire
• Relationships
• Child Development
• Therapy Center NEW
• Diagnosis Dictionary
• Types of Therapy

Understanding what emotional intelligence looks like and the steps needed to improve it could light a path to a more emotionally adept world.

• Coronavirus Disease 2019
• Affective Forecasting
• Neuroscience

Language and Speech Disorders in Children

Helping children learn language, what to do if there are concerns.

• Detecting problems

Children are born ready to learn a language, but they need to learn the language or languages that their family and environment use. Learning a language takes time, and children vary in how quickly they master milestones in language and speech development. Typically developing children may have trouble with some sounds, words, and sentences while they are learning. However, most children can use language easily around 5 years of age.

Parents and caregivers are the most important teachers during a child’s early years. Children learn language by listening to others speak and by practicing. Even young babies notice when others repeat and respond to the noises and sounds they make. Children’s language and brain skills get stronger if they hear many different words. Parents can help their child learn in many different ways, such as

• Responding to the first sounds, gurgles, and gestures a baby makes.
• Repeating what the child says and adding to it.
• Talking about the things that a child sees.
• Asking questions and listening to the answers.
• Looking at or reading books.
• Telling stories.
• Singing songs and sharing rhymes.

This can happen both during playtime and during daily routines.

Parents can also observe the following:

• How their child hears and talks and compare it with typical milestones for communication skills external icon .
• How their child reacts to sounds and have their hearing tested if they have concerns .

Learn more about language milestones .  Watch milestones in action.

  Top of Page

Some languages are visual rather than spoken. American Sign Language uses visual signals, including gestures, facial expressions, and body movement to communicate.

Some children struggle with understanding and speaking and they need help. They may not master the language milestones at the same time as other children, and it may be a sign of a language or speech delay or disorder.

Language development has different parts, and children might have problems with one or more of the following:

• Not hearing the words (hearing loss).
• Not understanding the meaning of the words.
• Not knowing the words to use.
• Not knowing how to put words together.
• Knowing the words to use but not being able to express them.

Language and speech disorders can exist together or by themselves. Examples of problems with language and speech development include the following:

• Difficulty with forming specific words or sounds correctly.
• Difficulty with making words or sentences flow smoothly, like stuttering or stammering.
• Language delay – the ability to understand and speak develops more slowly than is typical
• Aphasia (difficulty understanding or speaking parts of language due to a brain injury or how the brain works).
• Auditory processing disorder (difficulty understanding the meaning of the sounds that the ear sends to the brain)

Learn more about language disorders external icon .

Language or speech disorders can occur with other learning disorders that affect reading and writing. Children with language disorders may feel frustrated that they cannot understand others or make themselves understood, and they may act out, act helpless, or withdraw. Language or speech disorders can also be present with emotional or behavioral disorders, such as attention-deficit/hyperactivity disorder (ADHD) or anxiety . Children with developmental disabilities including autism spectrum disorder may also have difficulties with speech and language. The combination of challenges can make it particularly hard for a child to succeed in school. Properly diagnosing a child’s disorder is crucial so that each child can get the right kind of help.

Detecting problems with language or speech

If a child has a problem with language or speech development, talk to a healthcare provider about an evaluation. An important first step is to find out if the child may have a hearing loss. Hearing loss may be difficult to notice particularly if a child has hearing loss only in one ear or has partial hearing loss, which means they can hear some sounds but not others. Learn more about hearing loss, screening, evaluation, and treatment .

A language development specialist like a speech-language pathologist external icon will conduct a careful assessment to determine what type of problem with language or speech the child may have.

Overall, learning more than one language does not cause language disorders, but children may not follow exactly the same developmental milestones as those who learn only one language. Developing the ability to understand and speak in two languages depends on how much practice the child has using both languages, and the kind of practice. If a child who is learning more than one language has difficulty with language development, careful assessment by a specialist who understands development of skills in more than one language may be needed.

Treatment for language or speech disorders and delays

Children with language problems often need extra help and special instruction. Speech-language pathologists can work directly with children and their parents, caregivers, and teachers.

Having a language or speech delay or disorder can qualify a child for early intervention external icon (for children up to 3 years of age) and special education services (for children aged 3 years and older). Schools can do their own testing for language or speech disorders to see if a child needs intervention. An evaluation by a healthcare professional is needed if there are other concerns about the child’s hearing, behavior, or emotions. Parents, healthcare providers, and the school can work together to find the right referrals and treatment.

What every parent should know

Children with specific learning disabilities, including language or speech disorders, are eligible for special education services or accommodations at school under the Individuals with Disabilities in Education Act (IDEA) external icon and Section 504 external icon , an anti-discrimination law.

Get help from your state’s Parent Training and Information Center external icon

The role of healthcare providers

Healthcare providers can play an important part in collaborating with schools to help a child with speech or language disorders and delay or other disabilities get the special services they need. The American Academy of Pediatrics has created a report that describes the roles that healthcare providers can have in helping children with disabilities external icon , including language or speech disorders.

More information

CDC Information on Hearing Loss

National Institute on Deafness and Other Communication Disorders external icon

Birth to 5: Watch me thrive external icon

The American Speech-Language-Hearing Association external icon

Exit Notification / Disclaimer Policy

• The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
• Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
• You will be subject to the destination website's privacy policy when you follow the link.
• CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website.

An official website of the United States government

Here's how you know

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( Lock A locked padlock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Advancing the science of communication to improve lives

Apraxia of Speech

On this page:

What is apraxia of speech?

What are the types and causes of apraxia of speech, what are the symptoms of apraxia of speech, how is apraxia of speech diagnosed, how is apraxia of speech treated, what research is being done to better understand apraxia of speech, where can i find additional information about 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.

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 is aphasia , which is a language disorder. (For more information, see the NIDCD fact sheet 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.

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.

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.

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 speech-language 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.

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.

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.

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: [email protected]

NIH Pub. No. 13-7466 September 2016

• Patient Care & Health Information
• Diseases & Conditions

Dysarthria occurs when the muscles you use for speech are weak or you have difficulty controlling them. Dysarthria often causes slurred or slow speech that can be difficult to understand.

Common causes of dysarthria include nervous system disorders and conditions that cause facial paralysis or tongue or throat muscle weakness. Certain medications also can cause dysarthria.

Treating the underlying cause of your dysarthria may improve your speech. You may also need speech therapy. For dysarthria caused by prescription medications, changing or discontinuing the medications may help.

Products & Services

• A Book: Mayo Clinic Family Health Book, 5th Edition
• Newsletter: Mayo Clinic Health Letter — Digital Edition

Signs and symptoms of dysarthria vary, depending on the underlying cause and the type of dysarthria. They may include:

• Slurred speech
• Slow speech
• Inability to speak louder than a whisper or speaking too loudly
• Rapid speech that is difficult to understand
• Nasal, raspy or strained voice
• Uneven or abnormal speech rhythm
• Uneven speech volume
• Monotone speech
• Difficulty moving your tongue or facial muscles

When to see a doctor

Dysarthria can be a sign of a serious condition. See your doctor if you have sudden or unexplained changes in your ability to speak.

In dysarthria, you may have difficulty moving the muscles in your mouth, face or upper respiratory system that control speech. Conditions that may lead to dysarthria include:

• Amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease)
• Brain injury
• Brain tumor
• Cerebral palsy
• Guillain-Barre syndrome
• Head injury
• Huntington's disease
• Lyme disease
• Multiple sclerosis
• Muscular dystrophy
• Myasthenia gravis
• Parkinson's disease
• Wilson's disease

Some medications, such as certain sedatives and seizure drugs, also can cause dysarthria.

Complications

Because of the communication problems dysarthria causes, complications can include:

• Social difficulty. Communication problems may affect your relationships with family and friends and make social situations challenging.
• Depression. In some people, dysarthria may lead to social isolation and depression.
• Daroff RB, et al., eds. Bradley's Neurology in Clinical Practice. 7th ed. Elsevier; 2016. https://www.clinicalkey.com. Accessed April 10, 2020.
• Dysarthria. American Speech-Language-Hearing Association. https://www.asha.org/public/speech/disorders/dysarthria/. Accessed April 6, 2020.
• Maitin IB, et al., eds. Current Diagnosis & Treatment: Physical Medicine & Rehabilitation. McGraw-Hill Education; 2020. https://accessmedicine.mhmedical.com. Accessed April 10, 2020.
• Dysarthria in adults. American Speech-Language-Hearing Association. https://www.asha.org/PRPPrintTemplate.aspx?folderid=8589943481. Accessed April 6, 2020.
• Drugs that cause dysarthria. IBM Micromedex. https://www.micromedexsolutions.com. Accessed April 10, 2020.
• Lirani-Silva C, et al. Dysarthria and quality of life in neurologically healthy elderly and patients with Parkinson's disease. CoDAS. 2015; doi:10.1590/2317-1782/20152014083.
• Signs and symptoms of untreated Lyme disease. Centers for Disease Control and Prevention. https://www.cdc.gov/lyme/signs_symptoms/index.html. Accessed April 6, 2020.
• Neurological diagnostic tests and procedures fact sheet. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Neurological-Diagnostic-Tests-and-Procedures-Fact. Accessed April 6, 2020.

Associated Procedures

• EEG (electroencephalogram)
• Electromyography (EMG)
• Lumbar puncture (spinal tap)
• Symptoms & causes
• Diagnosis & treatment
• Doctors & departments

Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission.

• Opportunities

Mayo Clinic Press

Check out these best-sellers and special offers on books and newsletters from Mayo Clinic Press .

• Mayo Clinic on Incontinence - Mayo Clinic Press Mayo Clinic on Incontinence
• The Essential Diabetes Book - Mayo Clinic Press The Essential Diabetes Book
• Mayo Clinic on Hearing and Balance - Mayo Clinic Press Mayo Clinic on Hearing and Balance
• FREE Mayo Clinic Diet Assessment - Mayo Clinic Press FREE Mayo Clinic Diet Assessment
• Mayo Clinic Health Letter - FREE book - Mayo Clinic Press Mayo Clinic Health Letter - FREE book

Let’s celebrate our doctors!

Join us in celebrating and honoring Mayo Clinic physicians on March 30th for National Doctor’s Day.

What is a Speech Disorder?

Parents, doctors, and teachers become concerned when a child isn’t communicating well. It can be overwhelming when a child receives a diagnosis of a speech disorder because chances are it is not something that a parent or teacher has seen in the past. All of the synonyms for “speaking” such as speech, language, and voice mean very specific things to speech language pathologists but are generally referred to as “speech” or “speech therapy” by many.

Speech Disorders: Understanding the Different Types

Speech is a vital component of human communication. It is how we express our thoughts, ideas, and emotions to others. However, some people experience difficulties with their speech, which can affect their ability to communicate effectively. Speech language pathologists classify speech sound disorders based on error patterns that are being made or the cause of the sound errors.

When a family receives a diagnosis for a child or loved one these different descriptions can be confusing so that’s what we are going to cover here. Let’s talk about when we see speech disorders in children and adults and then the many different ways that sound errors can present themselves.

Speech Disorders in Children

According to a study published in the Journal of Speech, Language, and Hearing Research, speech sound disorders affect 8-9% of preschool children and up to 15% of school-age children. Early identification and intervention are crucial in helping children overcome their speech disorders. According to a study published in the Journal of Speech, Language, and Hearing Research, speech therapy can be highly effective in treating childhood speech disorders.

Speech Disorders in Adults

Speech disorders can also occur in adults, often due to neurological conditions such as stroke, traumatic brain injury, or Parkinson’s disease. According to a study published in the Journal of Communication Disorders, speech therapy can be effective in improving speech production in adults with neurological conditions.

What is a Speech Sound Disorder?

A speech sound disorder is a type of communication disorder that leads to an individual having difficulty producing certain sounds correctly. Identifying which aspect of “speech” to focus on is the key to improving and increasing a child’s communication.

Common speech disorders include:

Motor Speech Disorders

Motor speech disorders refer to difficulties with the planning and coordination of speech movements. These disorders affect the ability to produce sounds, words, and sentences. According to a study published in the Journal of Speech, Language, and Hearing Research, motor speech disorders are less common than speech sound disorders, affecting 2-3% of children.

Types of Motor Speech Disorders

There are two main types of motor speech disorders: apraxia of speech and dysarthria. Apraxia of speech is a disorder where the brain has difficulty planning and coordinating the movements needed for speech. Dysarthria, on the other hand, is a disorder where the muscles used for speech are weak or have difficulty moving.

Articulation Disorders

An articulation disorder is a type of speech sound disorder where an individual has difficulty producing certain sounds correctly due to issues with the movement of their mouth, tongue, or lips. According to a study published in the Journal of Speech, Language, and Hearing Research, articulation disorders are the most common type of speech sound disorder.

Types of Articulation Disorders

The two main types of articulation disorders are substitution and distortion. Substitution occurs when an individual substitutes one sound for another. Distortion occurs when an individual approximates a sound but does not produce it exactly right.

Phonological Delays

Phonological delays refer to difficulties with understanding and using the sound system of a language. According to a study published in the Journal of Speech, Language, and Hearing Research, phonological delays affect up to 10% of preschool children.

Types of Phonological Delays

A delay is a normal part of development, where a child’s acquisition of the sound system of a language is slower than average. A disorder, on the other hand, is a persistent difficulty with the sound system of a language.

Speech disorders are common and can affect individuals of all ages. Early identification and intervention are crucial in helping individuals overcome their speech difficulties. Speech therapy is a highly effective treatment for many types of speech disorders, and individuals should not hesitate to seek help if they are experiencing speech difficulties.

Our speech therapy programs start with a comprehensive evaluation in order to determine the area(s) of focus and the specific goals and objectives. Our evaluations include trial therapy to form impressions about how a child will respond to treatment.

Our SLPs are specialists at guiding all aspects of the therapy process. They choose WHAT to work on (i.e., targets), HOW it should be worked on (i.e., cues/strategies), and WHY it should be addressed (i.e., rationale).  Taking into account the age and interests of the patient, they use motivating activities and rewards. They develop unique programs based on the latest research to achieve the fastest progress possible.

Know that you are not alone.

Approximately one-in-ten children develop differently than their peers and may need support.   Contact us  today.

Additional resources:

Communication for a Lifetime  -ASHA.org

Definitions of Communication Disorders and Variations- ASHA.org

AddictionResource.com  raises awareness for the consequences of addiction and helps communities become drug-free.

HealthFinder.gov   promotes better health through education and awareness.

Get a complimentary continuing ed. course & E-book on Common Disorders.

30,000+ Subscribers

Sign up for weekly essays to improve your SLP life and practice!

And get a complimentary continuing ed. course & e‐book on Communication Disorders.

Find us on:

20 Spots Left! – SLP Study Abroad in Belize Info Session Friday 3/22

share this!

March 31, 2024

This article has been reviewed according to Science X's editorial process and policies . Editors have highlighted the following attributes while ensuring the content's credibility:

fact-checked

trusted source

written by researcher(s)

The Gambia may allow female genital mutilation again, another sign of a global trend eroding women's rights

by Satang Nabaneh, The Conversation

The Gambia's ban on female genital mutilation (FGM) since 2015 is under threat . Proposed changes before parliament could permit medicalized female genital cutting and allow it for consenting adults.

This potential reversal has thrust the country into the global spotlight as the latest example of the backlash against gender equality.

The Gambia's criminalization of FGM was not the first in west Africa but it came as a surprise. The president at the time, Yahya Jammeh, declared the rampant cultural tradition a non-religious practice that caused harm. There was some dissent within the country but human rights groups welcomed the ban.

Jammeh, who was president from 1994 to 2016, also oversaw the passage of other progressive gender-related laws. The Domestic Violence Act 2013 provided a framework for combating domestic violence in all its forms (physical, sexual, emotional, economic) and protection in particular for women and children. The Sexual Offenses Act 2013 expanded the definition of rape, broadened the circumstances in which individuals could be charged, and reduced the burden of proof in prosecutions.

Jammeh also outlawed child marriages in 2016. This was significant in country where 1 in 5 young people aged 15–19 (19%) are married.

In one of the world's most aid-dependent countries , these reforms were all central to international donor interests. And they helped to improve the country's democratic reputation. But at the same time, they made it easy for the autocratic leader to get away with other excesses. He also mobilized religion to manipulate beliefs and sentiments, particularly affecting girls and women. For example, Jammeh mandated that female government workers wear veils or headscarves when he declared his Muslim majority country an Islamic state in 2016.

President Adama Barrow, Jammeh's successor, has emphasized religious tolerance and has refrained from employing religious symbolism. Unlike the state-sponsored homophobia under the Jammeh regime, Barrow has downplayed homosexuality as a " non-issue ."

I am a legal scholar and human rights practitioner with published research on female genital mutilation , gender equality and women's rights and governance in The Gambia. It's my view that Jammeh's ostensible compliance with gender equality norms was selective and intended for the international gallery rather than a genuine commitment to women's rights and democracy.

His tactical stance highlighted a broader trend. Autocratic African leaders often accommodate global gender norms to maintain domestic power dynamics. The result, for example, is increased women's political participation through quotas along with a conservative approach to sexual and reproductive health and rights.

The Gambia experience also shows that western donors and multilateral institutions need to go beyond just pushing for reforms. Once they have got the reforms they advocated for, they should have a strategy for sustaining them. Forces that were opposed to the reform often regroup to campaign for its removal.

At its core, female genital mutilation constitutes a violation of the human rights of girls and women. These include the right to non-discrimination, to protection from physical and mental violence, and to health and life.

From a feminist perspective, the prevalence of FGM in numerous African nations revolves around upholding gender-specific norms and exerting control over women's sexuality.

Female genital mutilation in The Gambia

Female genital cutting is a deeply ingrained practice . It is driven by cultural beliefs and often performed by traditional healers. According to the most recent national survey , a large majority of Gambian women aged 15–49 years (73%) have undergone female genital cutting. More alarming is an 8% increase in the prevalence of FGM among girls under the age of 14—from 42.4% in 2010 to 50.6% in 2018.

Numerous health risks associated with all types of the practice have been documented by the World Health Organization and systematic reviews . These include severe pain, bleeding, infections and complications during childbirth and elevated rates of anxiety and other mental health disorders. This has led to calls for the practice to be banned in order to protect girls' health and well-being.

The Gambia's current struggle with the FGM ban reflects a complex interplay between cultural norms, religious beliefs, and the fight for gender equality. The potential repeal of the ban poses a threat to human rights of women and girls in The Gambia.

Reversal of hard-won gains

Though The Gambia is constitutionally secular, religion influences nearly every facet of society. Islamic fundamentalists in the country are known for attacks on religious minorities , including hate speech against the Ahmadiyya Muslim community and the Christian community .

The main fundamentalist religious actors draw inspiration from and still support the exiled former dictator Jammeh. They are at the forefront of the recent pushback against the anti-FGM law. They argue that the ban violates their religious and cultural freedoms as guaranteed in the 1997 constitution .

On 4 March 2024 a strong supporter of Jammeh proposed a private member's bill in the National Assembly that seeks to overturn the ban.

The push to reassert traditional gender roles isn't isolated to The Gambia. There is a global trend of rolling back progress on gender equality. This trend is characterized by attempts to limit women's bodily choices , an increase in violence against them, as well as attacks on LGBTQI+ communities. It reflects a broader political climate of backlash against women's rights and gender equality as a weapon in the reversal of democratic achievements.

Attempts have been seen to reverse legal protections against women and girls in Kenya . In Sudan, state-sanctioned violence and societal pressure is aimed at restricting women's public participation. Similarly, Tanzania previously enacted a policy barring teenage mothers from attending public schools, though this policy has been reversed.

This global context highlights how anti-rights movements, undemocratic norms and gendered politics are working together to erode women's rights and exacerbate inequalities.

Provided by The Conversation

Explore further

Feedback to editors

Simple equations clarify cloud climate conundrum

3 hours ago

Romania center explores world's most powerful laser

Mar 31, 2024

A cosmic 'speed camera' just revealed the staggering speed of neutron star jets in a world first

Mar 30, 2024

Saturday Citations: 100-year-old milk, hot qubits and another banger from the Event Horizon Telescope project

Curiosity rover searches for new clues about Mars' ancient water

Study says since 1979 climate change has made heat waves last longer, spike hotter, hurt more people

Scientist taps into lobsters' unusual habits to conquer the more than 120-year quest to farm them

Mar 29, 2024

Blind people can hear and feel April's total solar eclipse with new technology

Mapping the best route for a spacecraft traveling beyond the sun's sphere of influence

Researchers outline new approach in search for dark matter through future DUNE research project

Relevant physicsforums posts, cover songs versus the original track, which ones are better.

13 hours ago

How did ‘concern’ semantically shift to mean ‘commercial enterprise' ?

Interesting anecdotes in the history of physics.

22 hours ago

The new Shogun show

History of railroad safety - spotlight on current derailments.

Mar 27, 2024

Metal, Rock, Instrumental Rock and Fusion

More from Art, Music, History, and Linguistics

Related Stories

UNICEF: 230 million females are circumcised globally, 30 million more than in 2016

Mar 8, 2024

Why Gambia should fast-track gender quotas for women

Jan 28, 2022

Female genital mutilation/cutting is decreasing but more needs to be done

Sep 1, 2022

In France, abortion rights and hijab bans highlight a double standard on women's rights

Mar 16, 2024

Sexual and reproductive health rights of women, girls and marginalized people missing from most national climate plans

Oct 11, 2023

Nearly half of Britons say women's equality has gone far enough

Mar 4, 2024

Recommended for you

Song lyrics have become simpler and more repetitive since 1980, study finds

Mar 28, 2024

Low resting heart rate in women is associated with criminal offending, unintentional injuries

Your emotional reaction to climate change may impact the policies you support, study finds

Value-added tax data could help countries prepare better for crises

Survey study shows workers with more flexibility and job security have better mental health

Mar 26, 2024

We have revealed a unique time capsule of Australia's first coastal people from 50,000 years ago

Mar 25, 2024

Let us know if there is a problem with our content

Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. For general inquiries, please use our contact form . For general feedback, use the public comments section below (please adhere to guidelines ).

Please select the most appropriate category to facilitate processing of your request

Thank you for taking time to provide your feedback to the editors.

Your feedback is important to us. However, we do not guarantee individual replies due to the high volume of messages.

E-mail the story

Your email address is used only to let the recipient know who sent the email. Neither your address nor the recipient's address will be used for any other purpose. The information you enter will appear in your e-mail message and is not retained by Phys.org in any form.

Newsletter sign up

Get weekly and/or daily updates delivered to your inbox. You can unsubscribe at any time and we'll never share your details to third parties.

More information Privacy policy

Donate and enjoy an ad-free experience

We keep our content available to everyone. Consider supporting Science X's mission by getting a premium account.

E-mail newsletter