[coldtea]

Not sure about the specifics for Iran in particular (the grandparent can answer), I've just heard about that from some friends hailing from there.

But I could relate it, as it was a "chic" thing to do in my parts too back in the day (until around the 1970s), for upper class folks (using the polite forms of address, and so on).

A good analogy in English terms might be the flirting with all the speaking formalities in period movies live "Room with a view" or "Pride and Prejudice".

[throwaway2037]

FYI: Large parts of Afghanistan and Tajikistan also speak Persian. I was surprised to learn this recently.

[fsckboy]

fwiw, it's not so much that Persian is spoken in Tajikistan, it's that the Tajiks are a Persian people (as opposed to, in that part of the world, Turkic, Mongolic, or Hindi (Hindi and Urdu are the same languages, and Hindi and Persian are in the same broad language family, Indo-Iranian)