What physical feature limited the indian subcontinent’s contact with other people?

Southern India is home to the Deccan Plateau and several great rivers, and was home to many of the region's first indigenous peoples. The south remained largely unscathed by the Muslim invasions of the north. Here, Hinduism is the predominant religion and many of the languages are in a different language family than those of the north.

Yeah i’ll call ya tomorrow but i’m not sure if you wanna talk about it later