Dravidian languages
The origins of the Dravidian languages, as well as their subsequent development and the period of their differentiation are unclear, partially due to the lack of comparative linguistic research into the Dravidian languages. Though some scholars have argued that the Dravidian languages may have been brought to India by migrations in the fourth or third millennium BCE or even earlier, the Dravidian languages cannot easily be connected to any other language, and they could well be indigenous to India. Proto-Dravidian was spoken in the 4th or 3rd millennium BCE, and it is thought that the Dravidian languages were the most widespread indigenous languages in the Indian subcontinent before the advance of the Indo-Aryan languages.