Swahili (or Kiswahili) is a Bantu language spoken by various ethnic groups that inhabit several large stretches of the Indian Ocean coastline from northern Kenya to northern Mozambique, including the Comoros Islands. Although only 5–10 million people speak it as their native language,Swahili is a national, or official language, of four nations, namely Tanzania, Kenya, Uganda and the Democratic Republic of the Congo. Within the Congo, as in much of East Africa, it often acts as a lingua franca. It is the only language historically African in origin among the official working languages of the African Union.