English and Hindi are the two main business languages in India. Hindi and Urdu are fraternal twins. Hindi uses Devanagari writing system, and Urdu uses the Arabic/Farsi script. Both are used in India, Urdu is more common for Muslims in India and has more Persian loan words, and Hindi uses more Sanskrit based words (mostly more formal level). I studied Hindi for a little while with Utsav, and he is an excellent teacher for beginners. I recommend him highly. Most Indian teachers want to move too fast through the lesson materials. Utsav speaks excellent English also.
On Indian tv shows, they speak a Hindi/English hybrid. A lot of professionals prefer to speak in English. Indians tend to speak really, really fast so the accents take a while to get used to. Even when they speak English, it tends to sound like Hindi anyway by the speed and intonation.
In my opinion, most Indians are excellent at doing complex tasks but are really poor teachers. Indians are very friendly, kind and colorful people, but I recommend getting a basic level of Hindi or Urdu in order to prepare for an Indian partner.
Anil Anahato has a very good Hindi channel on Youtube. Hindipod101 is another good beginner Hindi channel.