Indian subcontinent is rich in languages. Individual communities have bee developed as economic and socal units through thousands of years of settlement and habitation. There is not much research on the old Indain languages, but many of them still sustain themselves as oral languages in the interior lands of the subcontinent. While its exact origin and genesis is still debated, what we know is that Sanskrit langauge became a dominant force to become a cultural binder of the subcontinent. The first comprehensive grammar for a language was compiled for Sanskrit language and the formalism helped produced elegant literature which registered the development of human creativity in the subcontinent. A parallel strewam of Tamil language also prevailed in the souther part of the peninsula and it also produced rich literature. Borrowing of words and metaphors among various parts of the country has continued through people migration, trade and commerce.
The following is a broad language map of India compiled in the '90s.