Pashtuns, sometimes spelled "Pushtuns", or "Pakhtuns", or "Pukhtuns", (, ), are the largest ethnic group in Afghanistan and the second largest in Pakistan. Their mother language is Pashto, but many of them also speak neighboring Urdu, Hindko and Dari languages. They are the original or native people of the area south of the Hindu Kush in Afghanistan and west of the Indus River in Pakistan. However, in the modern period, they have spread to cities outside their native land. According to researchers, the total population of the group is estimated to be around 50 million.