Glossary
CART captioning
CART 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.
Updated October 16, 20264 cited facts, each traced to its source
Also called CART, Communication Access Realtime Translation.
CART captioning is a live transcription service for people who are deaf or hard of hearing. A trained captioner listens to the speech in a meeting, class or event and types it in real time, and the words appear on a screen for the audience to read. The acronym CART stands for Communication Access Realtime Translation. The U.S. Department of Justice's guidance on the Americans with Disabilities Act uses a plainer name: real-time captioning, also known as computer-assisted real-time transcription 1.
CART is live captioning typed by a person
The service works like court reporting. A captioner uses a stenotype machine, a chorded keyboard on which several keys are pressed at once to produce whole syllables, words or phrases. Software turns those strokes into English text and shows it on a screen, a laptop or a projector. The captioner may be in the room or may work remotely over a video link.
The key difference from a transcript is timing. A transcript is written after the event. CART is written during it, so the reader sees the words while the speaker is still talking.
Example: a lecture with live captions
A student who is deaf attends a lecture. The university books a CART captioner for the session. The captioner types the lecturer's words, and the text appears on a screen at the front of the room and on the student's laptop, a few words behind the speaker. Questions from other students are typed as well, so the student can follow the whole discussion, not only the lecturer.
How fast does a captioner have to write?
The National Court Reporters Association sets the speed standard for court reporters. Its Registered Professional Reporter test requires the testimony and question-and-answer leg to be written at 225 words per minute 2. That is a test of court reporting, not of captioning, but it shows the level of skill that stenographic captioners train to. The stenotype machine, with its chorded keys, is what makes that speed possible, which is why CART is written by people with that training rather than by typists on an ordinary keyboard.
Accuracy falls under pressure, and automatic systems do not yet match trained captioners
Human CART is not perfect. A 2024 study of CART captioning, which proposed using large language models to help captioners, states that the accuracy of CART captioning "can considerably decline, thereby affecting the comprehension of DHH people" 3. The same authors report that existing approaches for improving automatic speech recognition "still fail to perform at par with trained CART captioners" 4.
That finding matters for anyone choosing between a human captioner and automatic captions. Automatic captions are quicker to arrange, but in the study's words they do not yet reach the level of a trained captioner. For a casual video, automatic captions may be enough. A fast, technical meeting with several speakers is where the gap matters most.
Why it matters for dictation
CART and dictation both turn speech into text, but they serve different people. Dictation is a tool a writer uses to draft their own words, and the writer checks the output. CART is a service a deaf or hard-of-hearing person uses to follow someone else's speech, and it has to be accurate on the first pass because the reader cannot check it against the audio.
The technology is related. Voice writing, in which a speaker repeats speech into a recognizer to produce clean text, is used in court reporting and captioning, and automatic speech recognition is the basis of most dictation apps. The same limits apply to both: noise, fast speech, unfamiliar names and overlapping voices all lower accuracy.
Related terms
- Stenotype: the chorded keyboard that CART captioners use.
- Voice writing: a speech-based method that is also used in captioning.
- Dictation: speaking text into a computer to write it, which is for the speaker's own draft.
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 U.S. Department of Justice's ADA guidance defines real-time captioning, also called computer-assisted real-time transcription or CART, as a service similar to court reporting in which a transcriber types what is said into a computer that projects the words onto a screen.
U.S. Department of Justice, Civil Rights Division, ADA.gov, 2026 · Original
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- 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.
- 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.
- DysarthriaDysarthria 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.
- 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
- Transcription: How to Turn Audio and Video Into TextTopic
- Speech to Text for Deaf and Hard of Hearing PeopleGuide
- Captions and Subtitles: Formats, Rules and ToolsGuide
- Stenography and Shorthand: Writing at 225 WPMGuide
- Are automatic captions good enough for accessibility rules?Question
- Do speech to text glasses work for deaf people?Question
- Is automatic captioning accurate enough for deaf people?Question
- Is there Live Transcribe for iPhone?Question
- Closed captions (CC)Glossary
- Real-time text (RTT)Glossary