One puts a trained human behind every caption. The other is always on, in a hundred languages, for a flat monthly cost. The honest answer about when each is the right call.
CART — Communication Access Realtime Translation — is what live captioning looked like before machines could do it, and in some rooms it is still what the best captioning looks like: a trained stenographer, writing at the speed of speech, with a human brain deciding what was actually said. AI captioning is the challenger that changed the economics. Neither wins everywhere — CART and AI captioning have different strengths, and the deciding factors are stakes, language, availability, and the preference of the person the captions are for. Here is the honest map.
A CART provider is a trained professional — typically from the court-reporting tradition — writing live captions on a stenotype machine or specialist software while people speak. The output appears on a screen for the person who needs it, in real time, with a human continuously judging context, speaker intent, and terminology.
That last point matters. When a university, employer, or court arranges CART as an accommodation, they are buying human judgment applied to every sentence — and for the person relying on it, that reliability is not an abstraction.
AI captioning replaces the stenographer with a speech-recognition engine. Three structural things change immediately:
No booking, no lead time, no coverage gaps. The unscheduled meeting, the hallway conversation that moves to a room, the 11 p.m. call — all capturable the moment they happen. This is the single biggest practical difference, and no amount of scheduling discipline closes it.
Instead of per-hour professional rates, AI captioning is a subscription — Unicaption runs $9 to $149 per month depending on tier. Captioning everything stops being a budget decision made meeting by meeting.
CART is largely an English service. An AI engine covers 60+ languages with automatic detection — and adds something CART never offered: live translation side by side with the original, which turns captioning into a multilingual tool rather than a monolingual accommodation.
Accuracy is the honest caveat. A modern streaming engine is strong on clear audio and ordinary speech, and it never tires. But it has no judgment: it cannot ask a speaker to repeat, flag that a term must be wrong, or push through truly broken audio the way a human writer can. What accuracy numbers do and don't tell you is a topic of its own — see Word Error Rate explained.
The framing for accommodations deserves care: the goal is effective communication for a specific person, and that person's stated preference is the strongest signal you have. Our guides to workplace accommodations for deaf and hard-of-hearing employees and ADA live captioning requirements cover the practical side — orientation, not legal advice.
Everywhere the deciding factor is availability, spontaneity, language, or scale. The meeting called twenty minutes ago. The organisation that wants every meeting captioned, not just the ones with a formal accommodation on file. The bilingual workplace where the need is translation as much as transcription. The student who wants captions in every lecture, including the ones no one scheduled coverage for.
There is also a class of need CART was never designed for: the multilingual one. When a team spans three languages, side-by-side live translation is the actual requirement — that is an AI-native capability, and it is why AI captioning shows up in multilingual team meetings that never involved an accessibility accommodation at all.
Mature accessibility programs run both: CART booked for the encounters that demand it, AI covering everything else. Unicaption is built to be that always-on layer:
| Situation | Better fit | Why |
|---|---|---|
| Formal accommodation, person prefers CART | CART | Preference governs; gold-standard reliability |
| Court or proceeding requiring certified provider | CART | The requirement is the answer |
| Unscheduled or same-day meetings | AI | No booking lead time exists |
| Captioning everything by default | AI | Flat cost makes universal coverage feasible |
| Multilingual meeting or translation need | AI | 60+ languages, live side-by-side translation |
| Terrible audio, one critical session | CART | Human judgment degrades gracefully |
| Both kinds of need across one organisation | Both | CART where mandated or preferred; AI everywhere else |
CART is billed like professional labor: per hour, usually with minimums, scheduled in advance, and rates vary by region, subject matter, and whether the writer works on-site or remotely — get current quotes from providers or agencies. AI captioning inverts the structure: Unicaption is a flat $9–$149 per month depending on tier, with no per-session cost, which is what makes captioning every meeting economically possible.
On clear audio with ordinary speech, modern AI is strong — Unicaption publishes state-of-the-art streaming accuracy — and it never fatigues. A skilled CART writer still wins where judgment matters: chaotic audio, dense unfamiliar terminology, and the ability to flag or clarify in the moment. The practical answer: test AI on your real audio (Unicaption's free tier gives you 30 minutes every week), and book CART for the sessions where a human's judgment is the requirement.
Sometimes, and only with the person's agreement. The accommodation standard is effective communication for that individual, and their stated preference matters — if someone requests CART, provide it. Many people are well served by high-quality AI captions, and many organisations use AI to extend coverage far beyond what CART budgets allowed. Treat this as practical orientation, not legal advice, and decide with the person, not for them.
Mostly no — CART is overwhelmingly an English-language service, with thin coverage elsewhere and nothing like translation. This is where AI captioning is categorically different: Unicaption transcribes in 60+ languages with automatic detection and shows a live translation side by side with the original, which covers multilingual meetings CART was never built for.
The always-on layer beside your CART bookings: state-of-the-art streaming accuracy, 60+ languages, live translation. 30 free minutes every week.
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