Hindi
How to get natural Hindi out of Syntic models, and what to check before you ship. The general rules for every language are on Work in other languages.
At a glance
| Language tags | hi-IN |
| Script and direction | Devanagari script, left to right |
| Token use | Measure with token counting on your own text; non-Latin scripts and long compounds usually take more tokens per sentence than English. |
Register and form of address
Everyday Hindi in India often mixes English words (Hinglish). Decide whether you want formal Hindi (शुद्ध हिंदी), conversational Hindi with common English terms, or Hinglish in Latin script, and say so.
Numbers, dates and currency
Indian number grouping: 1,23,45,678 with lakh and crore. Currency ₹. Dates: 05/11/2026 or 5 नवंबर 2026.
Common pitfalls
- Respectful address uses आप; तुम is familiar. Verb forms follow, so pick once.
- Technical terms (password, OTP, app) are usually clearer left in English, even in formal Hindi.
- Romanised Hindi has no standard spelling; if users write in Latin script, reply in the same script they used.
A system prompt line that works
Writing the language instruction in Hindi itself is a strong signal:
हिंदी में जवाब दें, उपयोगकर्ता को 'आप' कहकर संबोधित करें, और तकनीकी शब्द अंग्रेज़ी में ही रखें।(Answer in Hindi, address the user as आप, and keep technical terms in English.)
Keep the rest of your instructions in whichever language your team maintains best; the model follows mixed-language system prompts reliably, and the reply language follows this line.
Test before launch
- Collect 30 or more real Hindi messages, including short, misspelt and mixed-language ones.
- Have a fluent speaker grade replies for correctness, register and naturalness; then calibrate a rubric grader on their grades (Evaluate).
- Check rendering in your actual UI: line breaks, truncation and fonts.
- Re-run the set whenever you change the prompt or the model.