Geography and language distribution of India. In this map of India, all the states have been shaded according to the languages predominantly spoken in those states. The two broad language families are: (i) Dravidian (darker shade); and (ii) Indo-Aryan (lighter shade). There is a clear north–south divide, with northern states predominantly speaking Indo-Aryan languages such as Hindi, Marathi, Oriya, Punjabi and Gujarati; while southern states predominantly speak Dravidian languages such as Tamil, Malayalam, Kannada and Telugu. The two groups of samples used in this report trace their ancestries to different ethno-linguistic groups found at different geographical locations. The Houston Gujaratis (GIH) trace their ancestry to the Gujarati-speaking state of Gujarat (red star), while the Singapore Indians (INS) trace their ancestry predominantly to Tamil Nadu, a Dravidian-language speaking state in the south (grey star).