Swahili, also known as Kiswahili, is a Bantu language and the first language of the Swahili people. It is a lingua franca of the African Great Lakes region and other parts of eastern and southeastern Africa, including Tanzania, Kenya, Uganda, Rwanda, Burundi, Mozambique and the Democratic Republic of the Congo. The closely related Comorian language, spoken in the Comoros Islands, is sometimes considered a dialect.

Although only around 2 million (2003) to 15 million people speak Swahili as their first language, it is used as a lingua franca in much of Southeast Africa. Estimates of the total number of Swahili speakers vary widely, from 50 million to over 100 million. Swahili serves as a national language of three nations: Tanzania, Kenya, and the Democratic Republic of the Congo. Shikomor, the official language in Comoros and also spoken in Mayotte (Shimaore), is related to Swahili. Swahili is also one of the working languages of the African Union[citation needed] and officially recognised as a lingua franca of the East African Community.

A significant fraction of Swahili vocabulary is derived from Arabic through contact with Arabic-speaking Muslim inhabitants of the Swahili Coast. It has also incorporated German, Portuguese, English, Hindustani and French words into its vocabulary through contact with empire builders, traders and slavers during the past five centuries.

Source: Wiki