@52fighters I guess asking them to scream “Pakistan zindabad” (praising Pakistan) or “Hindustan Murdabad” (Down with India) can put them under stress. Especially if you insist that they shout it before proceeding with whatever they want to talk about. However, if I were in your place, I’d start pitching a sale for some made-up product to them.

It’ll be hard for you to know whether the people calling will know Hindi. If they’re calling from Delhi or New Delhi, the chances are high. If they’re calling from Mumbai, they might well be Marathi speakers instead. In Kolkata, the main language is Bengali. India is full of different languages.