Swahili 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, from 50 million to over 100 million. Swahili serves as a national language of four nations: Tanzania, Kenya, Uganda, and the DRC. Shikomor, the official language in Comoros and also spoken in Mayotte (), 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. South Africa legalized the teaching of Swahili in South African schools as an optional subject beginning in 2020.
Democratic Republic of the Congo
Approximately 242 languages are spoken in the country, but only four have the status of national languages: Kituba ("Kikongo ya leta"), Lingala, Tshiluba, and Swahili. Although some people speak these regional, or trade languages as first languages, most of the population speak them as a second language after their own tribal language. Lingala was the official language of the colonial army, the "Force Publique", under Belgian colonial rule, and remains to this day the predominant language in the armed forces. Since the recent rebellions, a good part of the army in the East also uses Swahili where it is prevalent.