Nubians are an ethnic group indigenous to the Nubia region, which stretches from southern Egypt to northern Sudan. They originate from the early inhabitants of the central Nile valley, believed to be one of the earliest cradles of civilization. In the southern valley of Egypt, Nubians differ culturally and ethnically from Egyptians, although they intermarried with them and other ethnic groups, especially Arabs. They speak the Nilo-Saharan Nubian languages as their mother tongue, which are part of the Northern Eastern Sudanic languages, and Arabic as a second language.