Horn of Africa complex pattern of interrelationships among the various groups. According to "Ethnologue", there are 10 individual languages spoken in Djibouti, 14 in Eritrea, 90 in Ethiopia, and 15 in Somalia. Most people in the Horn speak Afroasiatic languages of the Cushitic or Semitic branches. The former includes Oromo, spoken by the Oromo people in Ethiopia, and Somali, spoken by the Somali people in Somalia, Djibouti and Ethiopia; the latter includes Amharic, spoken by the Amhara people of Ethiopia, and Tigrinya spoken by the Tigrayan people of Eritrea and Ethiopia. Other Afroasiatic languages with a significant number of speakers include the Cushitic
Horn of Africa single landmass around 18 million years ago, before the Gulf of Aden rifted and separated the Horn region from the Arabian Peninsula. The Somali Plate is bounded on the west by the East African Rift, which stretches south from the triple junction in the Afar Depression, and an undersea continuation of the rift extending southward offshore. The northern boundary is the Aden Ridge along the coast of Saudi Arabia. The eastern boundary is the Central Indian Ridge, the northern portion of which is also known as the Carlsberg Ridge. The southern boundary is the Southwest Indian Ridge. Extensive glaciers once