ConditionBrain & nerves
Speech Disorders: Types, Causes and Treatment
Speech disorders are conditions that make it hard to produce speech sounds correctly, speak fluently, or use the voice normally. They include speech sound disorders (such as lisps), stuttering, childhood apraxia of speech, dysarthria and voice disorders. They are common in young children, affecting roughly 5 to 10%, and can also start in adults after a stroke or nerve disease. A speech-language pathologist diagnoses the type, and targeted speech therapy helps most people.
Also called: Speech impairment, speech-sound disorders, communication disorders, articulation disorders
At a glance
- What they are
- Problems producing speech sounds, keeping speech flowing, or using the voice.
- Main types
- Speech sound (articulation and phonological) disorders, stuttering, apraxia of speech, dysarthria, voice disorders.
- Who
- Most start in early childhood. Adult-onset speech disorders usually follow a stroke, brain injury or nerve disease.
- Diagnosis
- Assessment by a speech-language pathologist (SLP), plus a hearing test.
- Treatment
- Speech therapy; treating the underlying cause; communication aids when needed.
When to get help
Call 911 or go to the ER
- Sudden slurred or garbled speech, trouble finding words, facial droop or weakness in an arm or leg: call 911 or your local emergency number (possible stroke)
- Sudden speech loss with a severe headache, confusion or seizure
See a doctor within a day or two
- Speech that gets steadily slurred or weak over weeks, especially with swallowing problems or muscle weakness
- Hoarseness lasting more than 4 weeks, especially in smokers
- A child who loses speech or language skills they already had
Book a routine appointment
- No words by 16 months, or no two-word phrases by 24 months
- A 3-year-old whom strangers cannot understand most of the time
- Stuttering that lasts more than 6 months, starts after age 3½, or causes distress
- Persistent lisps or sound errors after age 7 to 8
Usually safe to manage at home
- Normal sound errors in toddlers, like "wabbit" for "rabbit" at age 3
- Brief, easy word repetitions in a 2- to 5-year-old that come and go
Speech vs language disorders
These terms are often confused:
- Speech is the physical production of sounds: articulation, fluency and voice.
- Language is the system of words and rules for understanding and expressing meaning.
A child who says "tat" for "cat" has a speech problem. A child who uses only a few words or cannot follow instructions has a language problem, such as developmental language disorder. Adults who lose the ability to find or understand words after a stroke have aphasia, a language disorder. Many people have both.
Types of speech disorders
| Type | What happens | Typical causes |
|---|---|---|
| Articulation disorder | Trouble making particular sounds, such as a lisp on "s" or difficulty with "r" | Often no clear cause; sometimes hearing loss or structural problems |
| Phonological disorder | Predictable patterns of errors, such as dropping final sounds ("ca" for "cat") | Developmental |
| Stuttering (fluency disorder) | Repetitions, prolonged sounds and blocks that interrupt speech | Genetic and neurological; often starts at ages 2 to 5 |
| Cluttering | Speech that is too fast and irregular, with dropped syllables | Developmental |
| Childhood apraxia of speech | The brain has trouble planning mouth movements; inconsistent errors | Neurological, sometimes genetic |
| Dysarthria | Weak, slow or uncoordinated speech muscles, causing slurred speech | Cerebral palsy, stroke, Parkinson's disease, ALS, MS, brain injury |
| Voice disorders | Hoarse, breathy, strained or absent voice | Vocal nodules, polyps, nerve paralysis, spasmodic dysphonia |
| Resonance disorders | Too much or too little sound through the nose | Cleft palate, enlarged adenoids |
Speech disorders in children
Typical speech milestones
| Age | What most children can do |
|---|---|
| 12 months | Babble with varied sounds, says 1 to 3 words |
| 18 months | Says around 10 to 20 words |
| 2 years | Uses 2-word phrases; strangers understand about half of their speech |
| 3 years | Uses 3-word sentences; strangers understand about 75% |
| 4 years | Strangers understand nearly all speech, though some sounds are still developing |
| 7 to 8 years | Most speech sounds, including "r", "s" and "th", are mastered |
Errors that are normal at 3 may be a disorder at 6, so age matters.
Causes and risk factors in children
- Family history of speech or language problems
- Hearing loss, including from repeated ear infections with fluid
- Premature birth or low birth weight
- Cleft lip and palate
- Neurological conditions such as cerebral palsy
- Autism spectrum disorder and developmental disabilities
- Genetic syndromes such as Down syndrome
Tongue-tie rarely causes speech problems by itself.
Speech disorders in adults
New speech problems in an adult are usually caused by:
- Stroke: sudden dysarthria, apraxia or aphasia. This is an emergency.
- Brain injury and brain tumors
- Progressive neurological diseases: Parkinson's disease (soft, monotone speech), ALS (slurred, nasal speech), multiple sclerosis, myasthenia gravis
- Voice problems: overuse, smoking, reflux, nerve damage after surgery, or throat cancer
- Acquired stuttering after brain injury or, rarely, as a reaction to stress
How speech disorders are diagnosed
- Hearing test, because even mild hearing loss affects speech development.
- Speech-language evaluation: an SLP listens to conversation and uses standardized tests of articulation, fluency, voice and oral motor skills.
- Oral mechanism exam of the lips, tongue, jaw and palate.
- Medical tests when needed: a neurological exam, brain MRI after sudden adult-onset speech changes, genetic testing in some children, and laryngoscopy (a camera view of the vocal cords) by an ENT doctor for voice problems lasting more than 4 weeks.
Treatment
Speech therapy
Speech-language pathologists tailor therapy to the type:
- Articulation and phonological therapy: practicing target sounds in syllables, words, then sentences, and contrasting sound patterns.
- Stuttering therapy: for young children, parent-led programs such as the Lidcombe Program; for older children and adults, fluency-shaping and stuttering-modification techniques, plus support for anxiety.
- Apraxia therapy: frequent, intensive practice of movement sequences with visual and touch cues.
- Dysarthria therapy: breathing support, slowing speech rate, exaggerating articulation; for Parkinson's, the LSVT LOUD program has good evidence.
- Voice therapy: vocal hygiene and techniques to reduce strain.
Other treatments
- Surgery for cleft palate or vocal cord lesions
- Botulinum toxin injections for spasmodic dysphonia
- Hearing aids or ear tubes for hearing problems
- Augmentative and alternative communication (AAC): picture boards, speech-generating devices and apps for people with severe speech impairment
How parents can help
Talk and read with your child daily, give them time to finish, model correct speech without demanding repetition, and limit background noise and screen time. Early intervention services in the US offer free evaluations for children under 3, and public schools evaluate children 3 and older.
Outlook
Most children with speech sound disorders improve significantly with therapy, and many reach normal speech. About 75 to 80% of children who start stuttering stop within a few years, often without treatment. Adults with dysarthria after stroke often improve over months. Progressive conditions benefit from therapy and communication aids that maintain independence.
Frequently asked questions
What are the main types of speech disorders?
The main types are speech sound disorders (articulation and phonological disorders, such as lisps), fluency disorders such as stuttering and cluttering, motor speech disorders including apraxia of speech and dysarthria, voice disorders such as hoarseness, and resonance disorders often linked to cleft palate.
When should I worry about my child's speech?
See your pediatrician if your child has no words by 16 months, no two-word phrases by 2 years, is hard for strangers to understand at 3, loses skills they had, or still has many sound errors after age 7. A hearing test and a speech-language evaluation are the next steps.
What causes speech disorders in adults?
The most common cause of sudden speech problems in adults is stroke. Others include brain injury, Parkinson's disease, ALS, multiple sclerosis, myasthenia gravis and brain tumors. Voice problems can come from overuse, smoking, reflux or nerve damage. Sudden slurred speech always needs emergency care.
What is the difference between a speech disorder and a language disorder?
A speech disorder affects how sounds are physically produced, how smoothly speech flows, or the voice. A language disorder affects understanding or using words and sentences to share meaning. A child may pronounce words clearly but struggle to form sentences (language), or form sentences well but mispronounce sounds (speech).
Can speech disorders be cured?
Many can be resolved or greatly improved. Most childhood speech sound disorders respond well to therapy, and many children who stutter recover. Adults with stroke-related speech problems often improve over months. Speech disorders from progressive disease cannot be cured, but therapy and communication aids keep people communicating.
Sources
This guide was written from current patient and clinical guidance, including:
- American Speech-Language-Hearing Association (ASHA): Speech Sound Disorders: Articulation and Phonology
- National Institute on Deafness and Other Communication Disorders (NIDCD): Speech and Language Developmental Milestones
- NIDCD: Stuttering
- MedlinePlus: Speech and Communication Disorders
- ASHA: Dysarthria in Adults