Convention Relating to the Status of Refugees. Ethnic groups The Arab population is estimated at 70% of the national total. They are almost entirely Muslims and speak predominantly Sudanese Arabic. Other ethnicities include Beja, Fur, Nubians, Armenians and Copts. Non-Arab groups are often ethnicially, linguistically and to varying degrees culturally distinct. These include the Beja (over 2 million), Fur (over 1 million), Nuba (approx. 1 million), Moro, Masalit, Bornu, Tama, Fulani, Hausa, Songhay, Nubians, Berta, Zaghawa, Nyimang, Ingessana, Daju, Koalib, Gumuz, Midob and Tagale. Hausa is used as a trade language.[where?] There is also a small, but prominent Greek community. Some Arab tribes speak other regional forms of Arabic, such as the Awadia and Fadnia tribes and Bani Arak tribes, who speak Najdi Arabic; and the Beni Ḥassān, Al-Ashraf, Kawhla and Rashaida who speak Hejazi Arabic. A few Arab Bedouin of the northern Rizeigat speak Sudanese Arabic and share the same culture as the Sudanese Arabs. Some Baggara and Tunjur speak Chadian Arabic. Sudanese Arabs of northern and eastern Sudan claim to descend primarily from migrants from the Arabian Peninsula and intermarriages with the indigenous populations of Sudan. The Nubian people share a common history with Nubians in southern Egypt. The vast majority of Arab tribes in Sudan migrated into Sudan in the 12th century, intermarried with the indigenous Nubian and other African populations and gradually introduced Islam. Additionally, a few pre-Islamic Arabic tribes existed in Sudan from earlier migrations into the region from western Arabia. In several studies on the Arabization of Sudanese people, historians have discussed the meaning of Arab versus non-Arab cultural identities. For example, historian Elena Vezzadini argues that the ethnic character of different Sudanese groups depends on the way this part of Sudanese history is interpreted and that there are no clear historical arguments for this distinction. In short, she states that "Arab migrants were absorbed into local structures, that they became “Sudanized” and that "In a way, a group became Arab when it started to claim that it was." In an article on the genealogy of different Sudanese ethnic groups, French archaeologist and linguist Claude Rilly argues that most Sudanese Arabs who claim Arab descent based on an important male ancestor ignore the fact that their DNA is largely made up of generations of African or African-Arab wives and their children, which means that these claims are rather more founded on oral traditions than