Vietnamese live captions and productivity tool for phone & video calls
For deaf and hard of hearing people.
coming soon
Download for free
Download on theApp Store
Everything you need to follow Vietnamese phone & video calls
Four tools built for deaf and hard of hearing Vietnamese speakers.
Follow the call in real time
- Captions appear word by word as the other person speaks
- Works on any call — no app integration required
- Put the call on speaker and point the microphone toward it
- Handles compressed call audio accurately
International and foreign-language calls
- They speak their language — you read in yours
- Translates in real time as they speak
- 60+ languages, no setup
- For family abroad, international business, or travel
Transcribe any call recording
- Record the call and upload for a complete written transcript
- Review instructions, information, and decisions after
- Organised by speaker
- Works on any call recording
Key information extracted from any call
- Important points pulled from any call transcript
- Useful for medical calls, customer service, and work calls
- Organised into clear sections
- Works on any saved recording
Download for free
Download on theApp StoreEvery situation covered
Designed for the real moments that matter — not just quiet controlled environments.
A catch-up call with parents or grandparents in Hanoi or Ho Chi Minh City. Family conversations carry six-tone Vietnamese at full speed. Captio AI captions everything said, as it is spoken.
A team meeting run in Vietnamese from a Ho Chi Minh City office or a Zoom call with Hanoi colleagues. Business Vietnamese with English technical terms. Captio AI keeps pace with both.
A callback from Bạch Mai Hospital in Hanoi or a prescription query from the local pharmacy. Medical Vietnamese uses formal register and clinical vocabulary. Captio AI shows the full message in text.
A Vietcombank automated IVR call or an MoMo customer service query in Vietnamese. Automated menus run at fixed speed with a timer. Captio AI captions each option before the timeout.
A call from the Vietnamese diaspora in the US, Australia, or Czech Republic. Diaspora Vietnamese carries foreign-language influence on vocabulary and rhythm. Captio AI handles it accurately.
A Zalo video call with family in Đà Nẵng or a Google Meet with a Hanoi team. All video call apps work the same way — put the call on speaker, open Captio AI, read the captions.
Most accurate and fastest models
word accuracy
independent benchmark, 2025
real-time captions
first word appears as you speak
Download for free
Download on theApp Store
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.
Why Vietnamese is hard to understand
Six-tone invisibility
- Every tonal distinction is encoded in pitch alone
- Vietnamese has six lexical tones (flat, falling, rising, broken, dipping, heavy). Every tonal distinction is encoded entirely in voice pitch and phonation quality — none has any visible lip or face change. On a phone or video call without hearing, every pair of words that differ only by tone (ma/mà/má/mả/mã/mạ — six different meanings) is completely indistinguishable.
Unreleased final stops
- Word-final stop consonants are silent and invisible
- Vietnamese word-final stops (-p, -t, -c, -ch) are unreleased — the mouth closes but no burst follows. These final consonants are invisible on lips and inaudible on a phone call, meaning the difference between bat (to catch), bac (silver/uncle), and bap (corn) is both acoustically and visually absent simultaneously.
Northern vs. Southern tone mergers
- Hanoi and Ho Chi Minh City use different tone systems
- Northern Vietnamese (Hanoi) maintains all six tones; Southern Vietnamese (Ho Chi Minh City) merges the ngã (broken/undulating) and hỏi (dipping) tones into one. A deaf caller from the south listening to a northern relative faces an additional tonal mismatch — even if they could hear the pitch, the tonal categories don't fully map.
Register gap
- Formal Vietnamese sounds completely different from casual speech
- Northern Hanoi Vietnamese uses a more measured, higher-pitched speech pattern while southern informal speech is faster and more relaxed. Formal calls — government offices, hospitals, banks — use a distinct register with vocabulary and pronunciation patterns that may not match the everyday speech a deaf caller is used to tracking.
Creaky and breathy phonation
- Two tones are encoded in voice quality, not pitch
- Vietnamese tones nặng (heavy) and sắc (rising) are realized partly through voice quality — creaky voice and glottalized onset. These phonation differences are entirely acoustic and invisible on lips. On a phone call without hearing, even the non-pitch component of the tonal system is lost.
Download for free
Download on theApp StoreFourteen hundred deaf children born in Vietnam each year, and no real-time phone access for any of them
Vietnam's Ministry of Health estimates that 1,200 to 1,400 children are born with hearing impairments each year — one of the highest rates of congenital hearing loss in Southeast Asia. Hearing disability is prevalent across age groups, with older adults and populations exposed to occupational noise in manufacturing and agriculture at elevated risk. The 2019 GBD study identified hearing loss as the leading cause of years lived with disability globally, and Vietnam carries a significant share of this burden.
Vietnamese Sign Language (Ngôn ngữ ký hiệu Việt Nam) is used in deaf communities with regional variants — Hanoi VSL and Ho Chi Minh City VSL differ significantly enough that signers from the two cities sometimes struggle to understand each other. There is no national relay telephone service for deaf callers on Viettel, Vinaphone, or VoIP platforms. Schools for deaf students in Vietnam that rely on lip reading have documented that the tonal dimension of Vietnamese is effectively inaccessible through vision alone.
Captio AI gives a deaf person in Đà Nẵng the ability to follow a Bạch Mai Hospital callback, navigate a Vietcombank IVR menu in Vietnamese, or join a Zalo family video call from Ho Chi Minh City — reading all six tones accurately as captions, in real time.
Download for free
Download on theApp StoreWhat 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.
Private by default
Download on theApp StoreCaptio AI supports 60+ languages
People love Captio AI
"Six Vietnamese tones and a phone call — completely impossible for me before. Captio AI reads them all accurately. Calls from my clinic with test results are now something I can handle on my own."
"Southern Vietnamese merges two of the tones that Hanoi Vietnamese keeps separate. When I call relatives in Hanoi I could never follow which tone they were using. Captio AI reads both varieties accurately — I can tell the words apart from the text."
"Zalo video calls with my grandmother in Đà Nẵng — she speaks central Vietnamese with different vowel patterns and tones. Captio AI follows it accurately. First time I've understood a full call with her without my mother translating."
"Vietcombank automated calls give you one reading of each option at normal speed with a timer. Captio AI shows each prompt before the timeout. I handle all my own banking now."
"Six Vietnamese tones and a phone call — completely impossible for me before. Captio AI reads them all accurately. Calls from my clinic with test results are now something I can handle on my own."
"Southern Vietnamese merges two of the tones that Hanoi Vietnamese keeps separate. When I call relatives in Hanoi I could never follow which tone they were using. Captio AI reads both varieties accurately — I can tell the words apart from the text."
"Zalo video calls with my grandmother in Đà Nẵng — she speaks central Vietnamese with different vowel patterns and tones. Captio AI follows it accurately. First time I've understood a full call with her without my mother translating."
"Vietcombank automated calls give you one reading of each option at normal speed with a timer. Captio AI shows each prompt before the timeout. I handle all my own banking now."
Download for free
Download on theApp StoreFrequently asked questions
Follow every call in Vietnamese.
Captio AI is free to start
coming soon
Download for free
Download on theApp Store