Captio AI
🦻 Accessibility + 💻 Productivity App

Korean 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 call with parents or grandparents in Seoul or a relative in Busan. Family conversations carry regional satoori, fast casual Korean, and the shorthand of close relationships. Captio AI captions everything said.

💼Work calls and conference calls

A team call in Korean from a Seoul office or a video meeting with Korean colleagues. Business Korean with honorifics and English technical vocabulary. Captio AI keeps pace with both.

🏥Medical and healthcare calls

A callback from Severance Hospital or a prescription query from a neighborhood pharmacy in Korean. Medical Korean uses formal vocabulary at speed. Captio AI shows the full message in text.

🏦Banks, utilities, and customer service

A Kakao Bank notification call or a KB Bank IVR menu in Korean. Automated menus give you one chance. Captio AI captions each option before the timeout.

🌍International calls

A call from the Korean diaspora in the US, Australia, or Southeast Asia. Diaspora Korean carries foreign-language influence on vocabulary and rhythm. Captio AI handles it accurately.

📹Video calls — FaceTime, WhatsApp, Zoom

A KakaoTalk video call with family in Incheon or a Zoom meeting with a Korean team. All video call apps work the same way — put the call on speaker, open Captio AI, read the captions.

Performance

Most accurate and fastest models

Korean
95.7%

character 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.

Korean

Why Korean is hard to understand

Three-way consonant contrast

  • Lax, aspirated, and tensed consonants look identical
  • Korean distinguishes three stop series: lax (ㅂ), aspirated (ㅍ), and tensed/fortis (ㅃ). Tensed consonants are produced with glottal constriction and no additional lip force — the distinction is entirely in the throat. On a phone call without hearing, all three series collapse visually. This affects dozens of high-frequency minimal pairs in Korean.

Identical vowel lip shapes

  • Several Korean vowel pairs look the same on lips
  • Korean vowel pairs like 아/어 (a/eo), 오/우 (o/u), and 이/으 (i/eu) look nearly identical on lips. The back-front distinction in 으/이 is entirely in tongue position with no lip spreading difference. These contrasts appear throughout common particles and verb endings — the most frequent elements in Korean speech.

Consonant lenition

  • The same consonant sounds different depending on position
  • In Korean, consonants at the syllable onset following a vowel become lax (lenited). This means the same consonant sounds different depending on its position: 밥 (bap) starts with the same letter as the second syllable of 밥을 (babŭl), but the second occurrence sounds softer. For a deaf caller tracking consonant identity, position-dependent shifts add a continuous disambiguation burden.

Seoul vowel mergers

  • Younger Seoul speakers collapse 애 and 에 into one vowel
  • Younger Seoul speakers have merged 애 (ae) and 에 (e) into a single vowel — a shift now dominant in urban Korean under 40. This merger is not reflected in writing, so pairs of words that were historically distinct now sound identical in the speech of most Korean callers under 40. A deaf caller cannot predict which words have merged.

Satoori regional variety

  • Busan, Gyeongsang, and Jeolla dialects use different intonation
  • Regional Korean varieties — Busan satoori, Gyeongsang, Jeolla — use different intonation patterns, prosodic stress, vowel realizations, and vocabulary from Seoul Korean. A deaf caller familiar with Seoul speech may not recognize fast Busan satoori even though both are Korean, particularly on a compressed phone call.

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The Challenge

Hearing impairment is the most common newly registered disability in South Korea — and phone access hasn't caught up

Around 5.3% of South Koreans report having hearing loss according to the 2024 KoreaTrak survey, with 5.9% among adults aged 18 and older. Hearing impairment accounts for 16.8% of all registered disabilities in South Korea, and at 31.7% of newly registered disability cases, it is the single most common new disability type registered annually. The total number of Koreans registered with hearing disabilities exceeded 400,000 by 2024.

South Korea's National Health Insurance has provided hearing aid subsidies for registered individuals with hearing disabilities since 1989, with the subsidy raised to approximately US$1,000 in 2015. Despite this policy support, only 19% of non-users believed they were eligible for financial assistance — indicating that awareness of state support remains critically low. Video relay services and caption phone access exist within registered DSP systems but are not available inside KakaoTalk, Zoom, or standard VoIP calls.

Captio AI lets a deaf person in Busan follow a KakaoTalk video call with family in Seoul, navigate a Kakao Bank automated menu, or read a Severance Hospital callback — without a caption phone subscription, without a relay number, on any smartphone.

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

"Hospital callbacks from Severance — the doctors speak fast formal Korean with medical vocabulary. Captio AI shows everything in text. I followed a full consultation callback without missing a word of the prescription instructions."

Ji-yeon P. 🇰🇷
jiyeon.p***@gmail.com
Moderate hearing loss, Seoul

"Busan satoori on a phone call is its own challenge — different intonation from Seoul Korean. Captio AI reads Busan satoori accurately. KakaoTalk calls with my grandmother in Gyeongsang are readable for the first time."

Minjun K. 🇰🇷
minjun.k***@gmail.com
Sensorineural hearing loss since birth, Busan

"KB Bank's phone menu in Korean is fast and automated. Captio AI shows each option in text with enough time to press the right key. I handle all my own banking calls now — no more asking my younger sister to do it."

Soyeon L. 🇰🇷
soyeon.l***@gmail.com
Hard of hearing, Daejeon

"KakaoTalk video calls with family in Incheon — the older generation speaks differently from my Seoul colleagues and I was getting lost. Captio AI follows both styles. I'm in every family call now instead of missing them."

Hyunwoo C. 🇺🇸
hyunwoo.c***@gmail.com
Age-related hearing loss, Los Angeles

"Hospital callbacks from Severance — the doctors speak fast formal Korean with medical vocabulary. Captio AI shows everything in text. I followed a full consultation callback without missing a word of the prescription instructions."

Ji-yeon P. 🇰🇷
jiyeon.p***@gmail.com
Moderate hearing loss, Seoul

"Busan satoori on a phone call is its own challenge — different intonation from Seoul Korean. Captio AI reads Busan satoori accurately. KakaoTalk calls with my grandmother in Gyeongsang are readable for the first time."

Minjun K. 🇰🇷
minjun.k***@gmail.com
Sensorineural hearing loss since birth, Busan

"KB Bank's phone menu in Korean is fast and automated. Captio AI shows each option in text with enough time to press the right key. I handle all my own banking calls now — no more asking my younger sister to do it."

Soyeon L. 🇰🇷
soyeon.l***@gmail.com
Hard of hearing, Daejeon

"KakaoTalk video calls with family in Incheon — the older generation speaks differently from my Seoul colleagues and I was getting lost. Captio AI follows both styles. I'm in every family call now instead of missing them."

Hyunwoo C. 🇺🇸
hyunwoo.c***@gmail.com
Age-related hearing loss, Los Angeles

Download for free

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FAQ

Frequently asked questions

Follow every call in Korean.

Captio AI is free to start

Download for free

Download on theApp Store