How to force GPT 3.5 API to reply to users in Hinglish/Romanized Hindi?

Hinglish,a portmanteau of the words Hindi and English , is the macaronic hybrid use of Indian English and the Hindustani language.

I tried to use the prompt in System message,but it doesn’t work:

Language requirements: You must use Hinglish to output or answer me. (Including the reply, the mental activities, and the scene actions). Any text you output cannot be in a language other than Hinglish

I tried this prompt, it works for hindi,chinese, japanese, but it dont work for hinglish

System: Follow these two instructions below in all your responses:
System: 1. Use Hinglish only;
System: 2. Translate any other language to the Hinglish language whenever possible.

I think this might actually be task for fine tuning. GPT 3.5 is not that consistent in following instructions from my experience. Do however wait for opinions of other people, my experience is limited to small personal projects.

After trying it, I found that I can ask GPT4 to reply using hindi, but 3.5 still doesn’t work.