What are the Most Common Speech Disorders?

Speech disorders impact millions of people and their ability to communicate. The National Institute of Deafness and Other Communication Disorders estimates that 5% of children in the U.S. ages 3 to 17 have had a speech disorder in the past 12 months. Some speech disorders can be overcome, while others are lifelong conditions. In either case, therapy with a speech pathologist can help a person make the most of their speech capabilities and develop alternative methods of communication. 

Speech pathologists or speech therapists complete a master’s program to be able to evaluate a person’s speech and communication, create a treatment plan and provide treatment to improve a person’s speech and other communication methods. Some speech pathologists’ careers deal with research and development treatment guidelines for various speech and language disorders.

What Is a Speech Disorder?

Speech is how people make sounds and words, according to the American Speech-Language-Hearing Association (ASHA). Speech problems can include the inability to make sounds clearly, having a raspy voice or stuttering (repeating sounds or pauses when speaking). 

Language is not the same thing as speech; it is the words we use to share ideas. Problems with language can include difficulty understanding, talking, reading or writing. 

According to ASHA, a speech disorder is an impairment of the articulation of sounds, fluency or voice. It is one of many types of communication disorders, which also include language and hearing disorders. 

Types of Speech Disorders

There are three categories of speech disorders

  • Articulation disorders: An unusual production of speech sounds involving substitutions, omissions, additions or distortions that might interfere with whether the sounds are intelligible to others.
  • Fluency disorders: Interruptions in the flow of a person’s speech, such as an uncommon rate, rhythm, or repetition of sounds, syllables, words or phrases.
  • Voice disorders: An abnormal production or absence of vocal quality, pitch, volume, resonance or duration that’s inappropriate for the person’s age and sex. 

Speech Disorder Causes

The medical community doesn’t know the cause of all speech disorders and, for many, the cause can vary. Potential causes for speech disorders include: 

  • Brain damage: Some speech and other communication disorders are due to a congenital condition. A child or adult who suffers a traumatic brain injury might sustain damage to a portion of the brain that impacts speech. Also, diseases and conditions such as stroke, dementia, Parkinson’s disease, ALS, Huntington’s disease, MS, cerebral palsy, muscular dystrophy, cancer and benign brain tumors can impact speech.
  • Nervous system condition: A disorder that affects a person’s nervous system can affect the muscles in their mouth, jaw, lips, or tongue or their vocal folds (voice box).
  • Nerve damage: Nerve damage in the voice box can impact the vocal folds and cause voice disorders, which are a type of speech disorder.
  • Stress: In some cases, it’s believed that stress can trigger certain speech disorders. 

10 Common Speech Disorders 

1. Childhood Apraxia of Speech

To talk, messages from the brain tell the muscles around the mouth and throat to move. In childhood apraxia, the messages don’t get through to the muscles correctly, according to ASHA. The child’s muscles aren’t weak, but they can’t move their mouth or tongue the right way to make the necessary sounds. The severity of this condition can vary. In more severe cases, a child might not be able to talk much. 

Childhood apraxia is not a developmental issue that a child can grow out of. With the help of a speech therapist, a child’s speech can improve. But ultimately, the way the child learns to make speech sounds won’t be typical of other children. 

2. Adult Apraxia

Apraxia of speech in adults is also called acquired apraxia of speech, verbal apraxia and dyspraxia. Adults suffer from verbal apraxia because of brain damage, such as a stroke, oxygen deprivation or a traumatic brain injury. 

Acquired apraxia in adults can affect their speech in various ways. A person might make a new sound, leave out sounds or say something the wrong way. They might not be able to make a sound the right way consistently. A person might have a hard time controlling their mouth, lips and tongue to make the right sounds. They might have to talk slowly. In severe cases, an adult might not be able to talk at all. 

3. Dysarthria

Dysarthria is the result of muscle weakness due to brain damage. The severity of the condition can vary, and it can be accompanied by other conditions, like speech apraxia. People with dysarthria might slur their words, speak slowly or too fast, talk softly, sound robotic and not be able to move their mouth or tongue well. Some people’s voices sound different than before their injury. 

4. Orofacial Myofunctional Disorders

People of any age can have an orofacial myofunctional disorder (OMD). An OMD might interfere with the development of the bones and muscles in a person’s face and mouth. This can impact a person’s ability to breathe, swallow, eat and talk. Various issues can cause an OMD, including anything that causes a person to rest their tongue in the right place or keep their lips together when at rest. 

One type of OMC is called tongue thrusting, which involves children pushing their tongue out when they try to talk, drink or eat. 

5. Speech Sound Disorders

A child who can’t correctly make speech sounds by 4 years old might have a speech sound disorder, also known as a phonological disorder or articulation disorder. Speech sound disorders are not only in children, though. Adults might have suffered from a disorder since childhood or acquired this disorder after sustaining brain damage. 

With a speech sound disorder, a person might make one sound in place of another, add sounds, change a sound or leave a sound out. The changes can be severe enough to make it hard for others to understand them. It’s important to note that people with accents will do some of these things, like replace one sound with another. An accent or dialect is not a speech sound disorder. 

6. Stuttering

A person who stutters might repeat whole words or sounds, stretch out sounds or have a hard time saying certain words. These are known as repetitions, prolongations and blocks, respectively. While everyone might stutter once in a while, stuttering becomes a speech disorder when it gets in the way of a person’s ability to communicate with others and is accompanied by negative feelings about talking. 

There’s no specific cause for stuttering. It might be the result of differences in children’s brains. In many cases, there’s a family history of stuttering. Most children start to stutter between the ages of 2 and 6 years. If the stuttering lasts for more than 6 months, then treatment with a speech pathologist might be necessary. 

7. Voice Disorders

Several conditions impact a person’s voice, and therefore, their ability to talk. These include:

Chronic cough: A cough that lasts more than four weeks in children and eight weeks in adults is considered chronic. It can alter the sound of a person’s voice or their ability to talk.

Paradoxical vocal fold movement: PVFM is when a person’s vocal folds (inside the voice box) close partly or all the way when they should open. This can cause breathing difficulties, change a person’s voice, or cause someone to lose their voice. PVFM can be triggered by acid reflux, stress, smoke, pollen, other allergens, exercise or breathing cold air, though no one knows the underlying cause.

Spasmodic dysphonia: With this long-term condition, a person’s vocal folds don’t move properly. A person with this disorder might not be able to speak all the time, though, at other times, their voice might sound normal. Their vocal folds might spasm or tighten when they talk, which can make them sound jerky or hoarse. A brain or nervous system disorder can cause this condition.

Vocal fold nodules and polyps: Growths on a person’s vocal folds can change their voice and cause discomfort and pain. This condition is usually caused by vocal abuse — typically long-term overuse or abuse.

Vocal fold paralysis: Vocal fold paralysis happens when one or both of your vocal folds can’t move. If they can’t come together, separate and vibrate, then a person doesn’t have a voice. It also causes issues with breathing and swallowing. When one fold is paralyzed, a person’s voice might be quiet. They might be limited in their pitch and tone and sound breathy. When two folds are paralyzed, the person might need a tracheotomy. 

8. Aphasia

Aphasia is technically a language disorder caused by brain damage to the left side of the brain. People with aphasia might have a hard time understanding other people, speaking, reading or writing. For example, a person with aphasia might hear another person and understand them, but then have a difficult time responding with the correct speech sounds. Aphasia can cause people to not remember the right word, say the wrong word, make up words, have a hard time speaking in full sentences or have a hard time speaking coherent sentences. 

9. Selective Mutism

Selective mutism is a childhood language disorder, often associated with a child being extremely shy, afraid of embarrassment, traumatized, wanting to be alone or having an anxiety disorder. A child might refuse to talk in certain situations, say in public or at school. 

10. Childhood Speech Delays

A child who is significantly delayed in developing their language and speech skills might have a language disorder. These are called preschool language disorders. Delayed speech is also called alalia. Some children have a hard time with receptive language, which helps them follow directions, understand gestures and answer questions. Others have difficulties with expressive language, like asking questions, naming objects or putting words together for a sentence. Some children have trouble with both. 

Speech Disorder Treatments

Many speech disorders cannot be cured, but by receiving speech and language therapy with a licensed speech pathologist, many children and adults can improve their speech or adapt to alternative communication methods. 

Speech therapists can help individuals learn the correct way to make a sound, including when and how to move their mouth and tongue, practice saying certain sounds, learn to tell when a sound is correct or wrong and practice using sounds in longer sentences. Speech pathologists can give children and adults exercises to improve their speech. Additionally, depending on the type of speech disorder, other medical or mental health care might be necessary. 

Speech disorders impact children and adults from all walks of life. But these disorders don’t have to stand in the way of their communication, education and careers. Licensed speech pathologists can help individuals improve their speaking, and when helpful, learn to use augmentative and alternative communication methods. 

Information last updated June 2020

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