The ethno-linguistic composition of the population of South Asia, that is the nations of India, Pakistan, Bangladesh, Nepal, Bhutan, Maldives and Sri Lanka, mostly falls within two large groups, Dravidian and Indo-Aryan. These groups are further subdivided into numerous sub-groups, castes and tribes. Indo-Aryans form the predominant ethno-linguistic group in Pakistan, India (the central, eastern, western and northern regions), Nepal, Sri Lanka and the Maldives. Dravidians form the predominant ethno-linguistic group in southern India and the northern and eastern regions of Sri Lanka. Iranian peoples, grouped with Indo-Aryans in the Indo-Iranian language group, also have a significant presence in South Asia, the large majority of whom are located in north-western Pakistan. Dardic peoples form a minority among the Indo-Aryans. They are classified as belonging to the Indo-Aryan language group[1] Previously, they have been classified as external to the Indo-Aryan branch[2], and are found in northern India and northern Pakistan. Minority groups not falling within either large group mostly belong to the Austro-Asiatic and Tibeto-Burman phyla. The Andamanese (Sentinel, Onge, Jarawa, Great Andamanese) barely subsist on some of the Andaman Islands and speak a language isolate, as do the Kusunda in central Nepal [3], the Vedda in Sri Lanka, and the Kalto (Nahali) of central India, who number about 5000 people. The people of the Hunza valley in Pakistan are another distinct population. They speak Burushaski, a language isolate.
The traditions of different ethnic groups in South Asia have diverged, influenced by external cultures, especially in the northwestern parts of South Asia (where Turkic and Iranian peoples have had much influence) and in the border regions and busy ports, where there are greater levels of contact with external cultures. The largest ethno-linguistic group in South Asia are the Indo-Aryans, numbering around 1 billion, and the largest sub-group are the native speakers of Hindi languages, numbering more than 300 million.