Swahili (Kiswahili) is spoken by various ethnic groups that inhabit several large stretches of the Indian Ocean coastline from southern Somalia to northern Mozambique, including the Comoros Islands. Although only 5-10 million people speak it as their native language, Swahili is also a lingua franca of much of East Africa and the Democratic Republic of the Congo, is a national or official language of four nations, and is the only language of African origin among the official working languages of the African Union. Swahili is a Bantu language that serves as an alternative first language to various groups traditionally inhabiting about 1,500 miles of the Southeast African coast.
About 35% of the Swahili vocabulary derives from the Arabic language, gained through more than twelve centuries of contact with Arabic-speaking traders. It also has incorporated German, Portuguese, English and French words into its vocabulary through contact during the last five centuries. Swahili has become a second language spoken by tens of millions in three countries, Tanzania, Kenya, and Congo (DRC), where it is an official or national language.
The neighboring nation of Uganda made Swahili a required subject in primary schools in 1992—although this mandate has not been well implemented—and declared it an official language in 2005 in preparation for the East African Federation. Swahili, or other closely related languages, is spoken by nearly the entire population of the Comoros and by relatively small numbers of people in Burundi, Rwanda, northern Zambia, Malawi, and Mozambique, and southern coastal Somalia. Native Swahili speakers once extended as far north as Mogadishu, and the language was understood in the southern ports of the Red Sea and along the coasts of southern Arabia and the Persian Gulf.
However, by the mid twentieth century its range in Somalia had contracted to Kismayo, Barawa, and the neighboring coastline and offshore islands, and in the 1990s many Bantu, including the Swahili, fled the Somali Civil War to Kenya. It is not clear how many remain.