Horn of Africa displays the greatest diversity, a sign often viewed to represent a geographic origin. The Horn of Africa is also the place where the haplogroup E1b1b originated from, Christopher Ehret and Shomarka Keita have suggested that the geography of the E1b1b lineage coincides with the distribution of the Afroasiatic languages. Genetic analysis done on the Afroasiatic speaking population further found that a pre-agricultural back-to-Africa migration into the Horn of Africa occurred through Egypt 23,000 years ago and it brought a non-African ancestry dubbed Ethio-Somali in the region. Together with northern Somalia, Djibouti, the Red Sea coast of Sudan and Eritrea is
Languages of Africa expansion, in which Bantu-speaking peoples expanded over most of Sub-Equatorial Africa, displacing Khoi-San speaking peoples from much of Southeast Africa and Southern Africa and other peoples from Central Africa. Another example is the Arab expansion in the 7th century, which led to the extension of Arabic from its homeland in Asia, into much of North Africa and the Horn of Africa. Trade languages are another age-old phenomenon in the African linguistic landscape. Cultural and linguistic innovations spread along trade routes and languages of peoples dominant in trade developed into languages of wider communication (lingua franca). Of particular importance in this