Swahili, also known as Kiswahili (translation: language of the Swahili people), 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 south-eastern Africa, including Kenya, Tanzania, Uganda, Rwanda, Burundi, some parts of Malawi, Somalia and Zambia, Mozambique and the Democratic Republic of the Congo (DRC). Comorian, spoken in the Comoros Islands, is sometimes considered to be a dialect of Swahili, though other authorities consider it a distinct language.
The exact number of Swahili speakers, be it native or second-language speakers, is unknown and a matter of debate. Various estimates have been put forward and they vary widely, ranging from 15 million to 50 million. Swahili serves as a national language of the DRC, Kenya, Tanzania, and Uganda. 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 and officially recognised as a lingua franca of the East African Community. In 2018, South Africa legalized the teaching of Swahili in South African schools as an optional subject to begin in 2020.
A significant fraction of Swahili vocabulary derives from Arabic, in part conveyed by Arabic-speaking Muslim inhabitants. For example, the Swahili word for "book" is kitabu, traceable back to the Arabic word كتاب kitāb (from the root K-T-B "write"). However, the Swahili plural form of this word ("books") is vitabu, rather than the Arabic plural form كتب kutub, following the Bantu grammar in which ki- is reanalysed as a nominal class prefix, whose plural is vi-.
(Courtesy of Swahili Language Wikipedia)