Nubian languages were spoken throughout much of Sudan, but as a result of Arabization they are today mostly limited to the Nile Valley between Aswan (southern Egypt) and Al Dabbah.
Old Nubian was written with a slanted uncial variety of the Coptic alphabet, with the addition of characters derived from Meroitic.
Old Nubian is currently considered ancestral to modern Nobiin, even though it shows signs of extensive contact with Dongolawi.
Additionally, important comparative work on the Nubian languages has been carried out by Thelwall, Marianne Bechhaus-Gerst in the second half of the twentieth century and Claude Rilly and George Starostin in the twenty-first.
Ethnologue's classification is based on glotto-chronological research of Thelwall (1982) and Bechhaus-Gerst (1996), which considers Nobiin the earliest branching from Proto-Nubian.