Captio AI
🦻 Accessibility + 💻 Productivity App

English live captions and productivity tool for phone & video calls

For deaf and hard of hearing people.

Download for free

Download on theApp Store
Captio AI app showing live captions

Download for free

Download on theApp Store
Use Cases

Every situation covered

Designed for the real moments that matter — not just quiet controlled environments.

👨‍👩‍👧Calls with family and friends

A catch-up call with a parent, a friend who doesn't know to slow down, a sibling calling from a noisy street. English family calls happen at full speed in any accent, with half-finished sentences and no warning.

💼Work calls and conference calls

A one-on-one with a manager, a team stand-up, a client update. English-medium work culture runs heavily on calls — a quick 'can you jump on a call?' is the default format for anything faster than email.

🏥Medical and healthcare calls

An NHS callback, a GP result, a pharmacy query, an appointment confirmation. Healthcare in the UK and US relies on phone for results and prescriptions — high-stakes calls where missing one word about a dosage has real consequences.

🏦Banks, utilities, and customer service

Bank security verification, automated IVR menus, insurance claims, utility billing disputes. English-language customer service is phone-first, with fast-speaking agents and automated systems that wait seconds for input.

🌍International calls

A call from an international colleague, a customer with an unfamiliar regional accent, a business contact in Australia or Canada. Global English accent diversity multiplies on top of phone compression.

📹Video calls — FaceTime, WhatsApp, Zoom

FaceTime with family, WhatsApp calls with friends, Zoom meetings with colleagues. Even with video available, lip reading at pace on a compressed stream is exhausting. Captions let you watch the person, not decode their mouth.

Performance

Most accurate and fastest models

English
93.5%

word accuracy

independent benchmark, 2025

< 200ms
you speak
captions

real-time captions

first word appears as you speak

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Captio AI in everyday use
Why Captio AI

Built for the calls you have been avoiding

Captions as they speak

Words appear on screen word by word while the other person is still talking. You read what they say at the same pace everyone else hears it — no delay, no reconstruction.

Works on any call app

Captio AI does not need to integrate with any platform. Put the call on speaker, point the microphone toward the audio, and read the captions. It works the same way for any app on any device.

No more asking for repeats

Every word is on screen as it is said. If you missed something, glance at the caption rather than interrupting the call — the full sentence is there.

Handles call audio accurately

Compressed phone audio is less clean than in-person speech. Captio AI is built for real-world audio conditions, including the reduced quality of standard phone and VoIP calls.

Any language

For calls with family abroad, international colleagues, or foreign-language customer service. Live Translator captions and translates in real time with no manual setup.

Record and review after

Record any call and upload it to Audio Transcription. Get a full written record of everything said — useful for medical instructions, work decisions, and anything worth having in writing.

English

Why English is hard to understand

Homopheme density

  • Many English consonants look identical on the lips
  • English has a high density of minimal pairs that are visually indistinguishable — 'park', 'bark', and 'mark' produce the same lip movement. On a phone call, the visual channel is gone entirely. The full cognitive load falls on compressed audio with nothing to fall back on.

Fricative collapse

  • Phone compression strips English's fricatives first
  • English relies heavily on fricative consonants — /f/, /v/, /θ/, /ð/, /s/, /z/, /ʃ/, /ʒ/. Narrowband phone audio (300–3400 Hz) strips the high-frequency information these sounds depend on, making 'think', 'sing', and 'thing' near-identical on a compressed line.

Accent diversity

  • No two English accents sound alike on a call
  • Scots, Geordie, Birmingham, RP, General American, Boston, Southern US — each accent places phonemes differently. On a phone call, a deaf caller calibrated to one variety faces a shifted phonological system with no visual anchor.

Fast speech reductions

  • Casual English systematically drops syllables
  • 'Probably' becomes 'probly', 'going to' becomes 'gonna', 'I don't know' becomes 'dunno'. These reductions appear in every informal register — family calls, work check-ins, customer service — at the speaker's natural pace, not the listener's.

Coarticulation blur

  • Connected English blurs word boundaries at speed
  • 'Did you eat yet?' runs into a single continuous sound at natural pace. Word boundaries that help a deaf person parse individual words disappear in fast connected English, leaving a dense acoustic stream with no visual segmentation.

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The Challenge

Eighteen million people with hearing loss in the UK alone

A 2024 analysis based on UK census data estimates that 18 million people in the United Kingdom have some degree of hearing loss — one in three adults. Of these, 12.3 million have bilateral loss affecting both ears. According to RNID's 2023 Health and Wellbeing Survey, 87% of people with hearing loss say it affects their daily communication, work, and relationships, and 62% report isolation or reduced confidence as a direct consequence.

Phone communication is the sharpest point of that exclusion. Research published in 2025 found that 55% of deaf respondents cite anxiety or frustration when relying on others to make calls on their behalf. More seriously, 20% of deaf and 24% of hard of hearing people surveyed said they had serious concerns that communication barriers would prevent them from reaching healthcare in an emergency. The phone call that arranges a GP appointment, reports a side effect, or clarifies a prescription is not optional — and for one in five deaf people, it is a genuine risk.

Captio AI is built for those calls. Put any English phone call on speaker — an NHS callback, a bank security check, a catch-up with a family member across an accent divide — and read the captions in real time. No relay operator, no third party, no asking anyone to slow down.

Download for free

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Privacy

What you hear stays with you.

Gone the moment it ends

Captio AI processes your audio in real time and discards it immediately. Nothing is recorded. Nothing is kept.

Not a product

Your conversations are not something Captio AI sells, shares, or monetizes — to anyone, for any reason.

Not used to train anything

What you say in a doctor's appointment or a job interview never ends up in a training dataset. Not ours. Not anyone else's.

100% PRIVATE

Private by default

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Reviews

People love Captio AI

"NHS callbacks were my biggest dread. I'd miss the doctor's name, the medication, the follow-up time. Now I put the call on speaker and read every word as it's spoken. I haven't needed to ring back for clarification once."

Sarah O. 🇬🇧
sarah.o***@gmail.com
Moderate hearing loss, Manchester

"Eight people on a conference call in different American accents — I used to catch maybe half. Captio AI on speaker and I follow everyone. I actually contribute in calls now instead of nodding and hoping I didn't miss something important."

James K. 🇺🇸
james.k***@gmail.com
Progressive hearing loss, Atlanta

"Video calls with my team in London were the hardest part of remote work — different accents, everyone talking fast. The captions appear before I've even looked up from my screen. I follow every call now."

Priya M. 🇦🇺
priya.m***@gmail.com
Hard of hearing, Sydney

"My bank locked my account and told me to call them. A year ago I would have asked someone else to make that call. I put it on speaker, answered every security question myself, got it sorted. That felt significant."

Tom B. 🇬🇧
tom.b***@gmail.com
Deaf, cochlear implant, Edinburgh

"NHS callbacks were my biggest dread. I'd miss the doctor's name, the medication, the follow-up time. Now I put the call on speaker and read every word as it's spoken. I haven't needed to ring back for clarification once."

Sarah O. 🇬🇧
sarah.o***@gmail.com
Moderate hearing loss, Manchester

"Eight people on a conference call in different American accents — I used to catch maybe half. Captio AI on speaker and I follow everyone. I actually contribute in calls now instead of nodding and hoping I didn't miss something important."

James K. 🇺🇸
james.k***@gmail.com
Progressive hearing loss, Atlanta

"Video calls with my team in London were the hardest part of remote work — different accents, everyone talking fast. The captions appear before I've even looked up from my screen. I follow every call now."

Priya M. 🇦🇺
priya.m***@gmail.com
Hard of hearing, Sydney

"My bank locked my account and told me to call them. A year ago I would have asked someone else to make that call. I put it on speaker, answered every security question myself, got it sorted. That felt significant."

Tom B. 🇬🇧
tom.b***@gmail.com
Deaf, cochlear implant, Edinburgh

Download for free

Download on theApp Store
FAQ

Frequently asked questions

Follow every call in English.

Captio AI is free to start

Download for free

Download on theApp Store