# What is AI dubbing?

> AI dubbing swaps the spoken language of a video for another one, with AI doing the translation and voice. How it works, how to test a dubbed ad and what to check.
- **Author**: Marxx
- **Published**: 2026-11-11
- **Category**: AI
- **URL**: https://marxx.ai/library-glossary/ai-dubbing

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AI dubbing swaps the spoken language of a video for another language. AI transcribes the speech, translates it and generates a new voice. You get one ad in many languages without a new shoot.

## How it works

1. The tool turns the original speech into text.
2. It translates the text.
3. It makes a voice that reads the translation, often matched to the speaker's tone and timing.
4. It lays the new audio over the video.
5. Optionally, [AI lip sync](/glossary/ai-lip-sync) redraws the mouth to match.

## Dubbing, subtitles and re-shoots

| | Subtitles | AI dubbing | Re-shoot |
|---|---|---|---|
| Viewer hears | The original language | The new language | The new language |
| Effort | Low | Low to medium | High |
| Mouth matches words | Yes, original | Only with lip sync | Yes |

## A worked example

Say you want to reach Hindi speakers with your 30-second English ad. You dub it into Hindi. You split one audience in two and show half the English original and half the Hindi dub, for 4 days at INR 500 a day each.

**Cost per purchase = ad spend / purchases**

- English original: INR 2,000 / 10 purchases = **INR 200**
- Hindi dub: INR 2,000 / 8 purchases = **INR 250**

The numbers are made up. Here the dub did not beat the original. That can happen when the audience reads English well. Keep audience, budget and days equal, so the language is the only difference.

## What to check

- **The translation.** Ask a native speaker to read it. Word-for-word translation can sound stiff.
- **On-screen text and captions.** Dubbing changes the audio, not the words in the picture.
- **Names and numbers.** Prices, product names and units must be read correctly.
- **Mouth movement.** On talking-head video, a mismatch shows. Add lip sync or cut to product shots.

Step-by-step help is in [how to dub ads into Hindi](/guides/how-to-dub-ads-into-hindi). To compare tools, see the [best AI dubbing tools](/best/best-ai-dubbing-tools). If the dub keeps the original speaker's voice, read about [AI voice cloning](/glossary/ai-voice-cloning).

Marxx has a production canvas for image, video, voice, dubbing, avatars and UGC that publishes campaigns, ad sets and ads to Meta. See [the production canvas](/features/production-canvas).

## FAQ

### Is AI dubbing the same as subtitles?

No. Subtitles add text over the original audio. Dubbing replaces the audio.

### Does AI dubbing use my voice?

Some tools can keep the original speaker's voice style in the new language. Check the tool's settings and only use a voice you have permission to use.

### Do I need lip sync?

Only for videos where a face talks to the camera. Voiceover over product shots does not need it.

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