# Vietnamese speech-to-text API (Tiếng Việt)

> KolWrite transcribes Vietnamese audio and video with one API call: send "language": "vi" and get tone-marked Vietnamese text in timed segments with speaker labels, as JSON, TXT or SRT. Oracle models translate Vietnamese into English or 99 other languages.

Last updated: 2026-10-08 · HTML: https://console.kolwrite.com/speech-to-text/vietnamese

## Transcribe Vietnamese with one request

Set `language` to `vi` and start a job. Poll `GET /transcribe/{jobId}` for the result, or pass a `webhook_url`.

```bash
curl https://app.kolwrite.com/transcribe \
  -H "x-api-key: $KOLWRITE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"audio_url": "https://example.com/phong-van-vi.m4a", "model": "oracle", "language": "vi", "include_diarization": true, "output_format": "json"}'
```

Translate Vietnamese audio into English in the same job (Oracle models only):

```bash
curl https://app.kolwrite.com/transcribe \
  -H "x-api-key: $KOLWRITE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"audio_url": "https://example.com/phong-van-vi.m4a", "model": "oracle_mini", "language": "vi", "translate_to": "en", "output_format": "srt"}'
```

## Vietnamese at a glance

| Property | Details |
| --- | --- |
| API code | `vi` |
| Native name | Tiếng Việt |
| Writing direction | Left to right |
| Automatic detection | Yes: omit `language` or send `"auto"` |
| Translate Vietnamese audio into | Any of the 100 supported languages, on Oracle models |
| Translate other languages into Vietnamese | Yes: `translate_to: "vi"` on Oracle models |
| Output | JSON (segments, word timings, speakers), TXT, SRT |
| Price | US$0.48 (Base) to US$3.60 (Oracle Max) per audio hour; US$1.44 on Oracle |

## What to know about Vietnamese transcription

- Vietnamese is tonal and its Latin script stacks diacritics (ế, ợ). Store text in Unicode NFC; mixing NFC and NFD breaks search and comparison.
- Northern, Central and Southern accents differ noticeably. There is no regional setting; test the regions you serve.
- Vietnamese words are written syllable by syllable with spaces, so word timestamps usually align to syllables.

## Where teams use Vietnamese transcription

- Customer calls and sales for companies in Vietnam.
- Vietnamese video and e-learning subtitles.
- Interviews translated to English with `translate_to: "en"`.

## Choosing a model

Start with `oracle` (US$1.44 per hour) for production Vietnamese audio. Use `base` (US$0.48) for clean, single-speaker recordings at volume, `oracle_mini` (US$0.96) for the cheapest translation, and `oracle_pro` or `oracle_max` for noisy or difficult audio. KolWrite does not publish a Vietnamese accuracy figure for this API, so test a sample of your own recordings before committing. Full comparison: [models and prices](https://console.kolwrite.com/models).

## Questions and answers

### Why does my Vietnamese search fail on identical-looking words?

Different Unicode normalization. Normalize transcripts and queries to NFC.

### Are regional accents supported?

All Vietnamese is sent as `vi`. Test recordings from each region you serve.

### Can I translate Vietnamese to English?

Yes, on an Oracle model with `translate_to: "en"`.

## Related pages

- [Thai speech-to-text](https://console.kolwrite.com/speech-to-text/thai)
- [Indonesian speech-to-text](https://console.kolwrite.com/speech-to-text/indonesian)
- [Chinese speech-to-text](https://console.kolwrite.com/speech-to-text/chinese)
- [Call centers & sales calls](https://console.kolwrite.com/use-cases/call-centers)
- [Universities & students](https://console.kolwrite.com/use-cases/education)
- [Supported languages](https://console.kolwrite.com/languages/)

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Get an API key: https://console.kolwrite.com/auth · API documentation: https://console.kolwrite.com/public_api_docs · llms.txt: https://console.kolwrite.com/llms.txt