I answered Hindustani
Hindustani means "The Country of India", it isn't a language. India has many languages (not dialects) with different scripts and people who can't understand each other unless they're speaking English (or Hindi - the national language). Quick Indian language lesson (note I'm married to an Indian woman, and have spent a lot of time there):
Hindi - national language of India, not to be confused with the majority religion, Hinduism (Hindu)
English - spoken by most everyone
Gujurati - spoken by the vegetarian community of Gujurat
Bengali - spoken by folks in West Bengal (like Kolkata / Calcutta) (including my wife and I)
Marati - spoken by folks in Maharashtra, where Mumbai / Bombay is located
Kannada - spoken by folks in Karnataka, where Bangalore (Silicon Valley of India) is located
Urdu - very similar to Hindi, but spoken by Muslims. Totally different script
Sanscrit - ancient language that is to Indian languages what Latin is to Western European languages
Pali - an even older language that was the root of Sanscrit
........and about 300 other languages that are too numerous to list.
The good news is they almost all speak english, and unlike most parts of the world, consider Americans like Rock Stars (they like our technology, and our money), so it's a good place to visit, especially if you like spicy food
Matt