English is the lingua franca in India for a reason, one of the things I found interesting about the British Raj, is, the english sowed the seeds of tools of their own exit - Railways, English and Civil Society (specifically the Indian Civil Service and some vague ideals of Democracy).
Those three things took the area that comprised British India, from a bunch of loosely connected nation-states, each with their own cultures, languages, and religions - while still having much in common, but not something that was easily unifiable, to something much more cohesive, to something that could be united.
Then leaders came along who were educated in Britain, filled with British democratic ideals who learned how to subvert to colonial system from within. Who then did so, they wrestled what was considered the crown jewel of the empire from the British, with the tools the British gave them. It's still a brilliant feat, because it used colonialism to subvert and ultimately defeat colonialism.
None of this should be construed as a defense of the Raj, or to imply that India could not have unified itself without those tools, but it turned an impossibly gargantuan task into a merely very hard one, because those tools allowed (at least temporarily) for people to overcome sectarian differences, and work together as one people towards a common goal with a common understanding.
I wish people knew more about partition however, partition is the greatest humanitarian crisis the world knows nearly nothing about, it rivals even the holocaust in size, and it didn't have to happen, but for a lack of trust between the Indian National Congress and the Muslim League. I believe that India, Pakistan and Bangladesh would be stronger today if it was one nation rather than three.