Swahili, Congo (swc-swc) = 3 (Wider communication). Statutory language of national identity (2006, Constitution, Article 1(8)). In the 19th century, traders from the Swahili coast on the shores of East Africa settled in the eastern part of the present-day Democratic Republic of Congo in search of ivory and slaves. It is now the most widespread lingua franca spoken in Eastern Equatorial Africa.