Glossary
Dysarthria
Dysarthria is a speech disorder that happens when brain or nerve damage changes the way the muscles used for speaking work, so speech can sound slow, slurred or hard to understand. Speech recognition trained on typical voices can make more errors with this speech, so accuracy depends on the person and the software.
Updated October 16, 20264 cited facts, each traced to its source
Dysarthria is a speech disorder that happens when brain or nerve damage changes the way the muscles used for speaking work. The American Speech-Language-Hearing Association says the result can be speech that sounds slow, slurred or hard to understand 1.
Which muscles are involved
Talking uses many muscles. The association lists the muscles in the face, lips, tongue and throat, along with the muscles used for breathing 2. Dysarthria affects how those muscles are controlled, so a person may know exactly what they want to say and still be hard to follow.
Signs and severity
Dysarthria can be mild or severe, and it can affect children and adults. Some people with dysarthria also have other speech or language difficulties, such as apraxia of speech, which affects how the brain plans movements for talking, or aphasia, which affects understanding and expression. A speech-language pathologist can assess an individual's speech and advise on how to communicate.
Example: a voice assistant that misses most words
A person with dysarthria after a stroke dictates a message. The software writes a string of wrong words, so they repeat the sentence several times, which is tiring. The problem is the match between the voice and the software, not the person's intelligence or intent. In one study, a baseline recognizer with a 3.4 percent word error rate on typical speakers had a 36.3 percent word error rate on speech from people with Parkinson's disease 3. Fine-tuning the recognizer on Speech Accessibility Project recordings reduced that error rate to 23.7 percent in the same study.
Why it matters for dictation and typing
Speech recognition is not equally accurate for every voice. Apple's Listen for Atypical Speech, announced in May 2024, uses on-device machine learning to recognize a user's speech patterns, and it is designed for people with acquired or progressive conditions that affect speech, such as cerebral palsy, ALS or stroke 4. People with dysarthria may find that a standard dictation tool works poorly, so testing it first and keeping a keyboard or switch access as a fallback is sensible. For ways to plan this, see the guide on speech recognition for speech impairments.
Related terms
- Augmentative and alternative communication (AAC): communication methods for people who cannot rely on speech.
- Assistive technology (AT): the devices and software that support speaking and writing.
- Dictation: speaking so that software writes your words.
Guides that cover it
Evidence
Every number on this page, with where it comes from. Open a fact to see the exact words in its source.
- 1.The American Speech-Language-Hearing Association says dysarthria is a speech disorder that happens when brain or nerve damage changes the way the muscles used for speech work, which can make speech slow, slurred or hard to understand.
American Speech-Language-Hearing Association (ASHA), 2026 · Original
- 2.
- 3.A baseline speech recognizer with a 3.4 percent word error rate on typical speakers had a 36.3 percent word error rate on speech from people with Parkinson's disease; fine-tuning on Speech Accessibility Project data reduced it to 23.7 percent.
Mark Hasegawa-Johnson et al., Journal of Speech, Language, and Hearing Research, 2024 · Original
- 4.
Related terms
- Speech to Text for Accessibility, RSI and DisabilitiesThe topic this term belongs to
- Access to WorkAccess to Work is a UK government grant for people with a disability or health condition who need support to do their job. GOV.UK says it can help pay for specialist equipment and assistive software, among other support, and that the grant does not affect other benefits and does not have to be paid back.
- Assistive technology (AT)Assistive technology (AT) is any item, piece of equipment or product system that increases, maintains or improves what a person with a disability can do. Speech recognition, voice control and screen readers are common examples.
- Augmentative and alternative communication (AAC)Augmentative and alternative communication (AAC) is a clinical practice area that supplements or compensates for impairments in speaking or understanding language. It uses tools such as picture boards, letter boards and speech-generating devices, and it is augmentative when used alongside speech and alternative when used instead of speech.
- CART captioningCART captioning is a live text service in which a trained captioner types what is said, usually on a stenotype machine, and the words appear on a screen as they are spoken. CART stands for Communication Access Realtime Translation, and it is also called real-time captioning.
- De Quervain's tenosynovitisDe Quervain's tenosynovitis is a painful condition in which tendons that move the thumb become irritated where they pass through a narrow tunnel on the thumb side of the wrist. Repeated thumb and wrist movements, such as texting, can worsen it.
- Disabled Students' Allowance (DSA)Disabled Students' Allowance (DSA) is UK government support for students with a disability, mental health problem or long-term illness, to cover study costs that come from the condition. It depends on individual needs rather than household income, and it does not have to be paid back.
- DysgraphiaDysgraphia is a difficulty with writing that does not match a person's cognitive level and age, even after adequate instruction. It can affect letter formation, spacing, spelling, writing speed and composition, and speech to text lets a person get their words onto the page without writing each letter by hand.
- Individualized Education Program (IEP)An Individualized Education Program (IEP) is a written statement for a child with a disability, developed, reviewed and revised under the federal IDEA regulations. For US students, it is the school's plan for the special education and services the child needs, and the team must consider whether the child needs assistive technology.
- Median nerveThe median nerve is one of the main nerves of the arm. It runs from the forearm through the wrist into the hand, giving feeling and movement to parts of the hand.
- Reasonable accommodationA reasonable accommodation is a change to the job, the workplace or the equipment that lets a qualified person with a disability do the work. Under U.S. law, employers with 15 or more employees must provide one unless it would impose an undue hardship.
- Repetitive strain injury (RSI)Repetitive strain injury (RSI) is an umbrella term for pain and damage to muscles, tendons and nerves that builds up from repeated movements, held postures or sustained effort, felt in the hands, wrists, arms, shoulders and neck.
- Screen readerA screen reader is software that reads what is on a computer or phone screen aloud, or sends it to a braille display, so that people who are blind or have low vision can use the device. The most used screen readers on Windows are JAWS and NVDA, and VoiceOver is the one built into Apple devices.
Pages that use this term
- Speech to Text for Accessibility, RSI and DisabilitiesTopic
- The Future of Typing: Voice, AI and the KeyboardGuide
- Speech Recognition for Stuttering and DysarthriaGuide
- Can voice recognition understand dysarthric speech?Question
- How accurate is voice recognition software?Question
- What is silent speech, and can you dictate without speaking aloud?Question
- What is the best voice to text app for elderly people?Question
- Which speech recognition apps work for atypical speech?Question
- Augmentative and alternative communication (AAC)Glossary