AI video · 10 Mar 2026 · 6 min read
How to write Hindi dialogue prompts with lip-sync
How to get AI video characters to speak Hindi and Hinglish lines with mouth movement that actually matches the words.
Dialogue is where AI story videos feel real or fall apart. The good news: Veo 3 handles Hindi and Hinglish dialogue well — if you prompt it correctly. Most lip-sync failures come from three missing instructions, not from the model.
Always name the language
Never assume the model will detect the language from the dialogue text. State it explicitly: 'speaking in Hindi' or 'speaking in Hinglish'. Without this, the model often mouths English-shaped sounds over your Hindi line and the sync is wrong from the first frame.
Keep lines short
Eight to twelve words fit an eight-second clip at a natural speaking pace. 'मैंने तुम्हें बुलाया था, पर तुम नहीं आए।' is perfect. A thirty-word emotional speech will be rushed, and rushed speech is exactly when lip-sync breaks. Split long lines across two scenes with a reaction shot between them.
Add the lip-sync instruction
End the dialogue section with an explicit instruction: 'mouth movement matches the spoken words, natural lip-sync'. It feels redundant. It is not. Scenes with this line sync noticeably more often than scenes without it.
Describe the voice, not just the words
Your character block should include a voice description: 'warm young male voice, slight Delhi accent' or 'soft female voice, calm tone'. Reuse it word for word in every scene so the voice stays as consistent as the face.
Frame dialogue as a close-up
Lip-sync is judged on the mouth. A wide shot hides sync problems but wastes the dialogue; a close-up or medium close-up is where dialogue scenes belong. Save wide shots for action and establishing beats.
A complete dialogue block example
Dialogue: Ravi says in Hindi, 'मैंने तुम्हें बुलाया था, पर तुम नहीं आए।' Warm young male voice, slight Delhi accent, disappointed tone. Mouth movement matches the spoken words, natural lip-sync. That is the whole recipe — language, short line, voice, sync instruction.
The AI Video Prompt Builder has a dedicated dialogue field with a language picker, so these instructions are added to every scene automatically.