I would like to draw some comments about the nature of the transformation that took place after 1800 BC, the spread of the Harappan culture over different parts of the subcontinent and their linkages with some of the Megalithic cultures of South India, non-Harappan Chalcolithic cultures and Vedic cultures. Submittted by Narottam Vinit
I refer to my earlier replies concerning Elamite and Tamil, and the Vedic people. The megalithic culture of the Deccan, South India and Sri Lanka seems to owe its origin to the immigration around 800 BCE of originally Old Iranian speaking and horse-riding peoples, who in northern India became Indo-Aryanized as the "Pandavas" of the Mahabharata war, while in the southward spread they became linguistically Dravidianized. I have discussed this e.g. in my paper in the Journal of the American Oriental Society 122 (2002).