The majority of the population is concentrated along the railroad between Pointe-Noire and Brazzaville in the south where Kituba (a creole language based on Kikongo) is the primary language.
The Kongo peoples are divided into many subgroups including the Yombe, Vili, Beembe, Sundi, and others but share a common language, Kikongo.
In its earliest attestations in Kikongo dialects in the early seventeenth century it was spelled "mokissie" (in Dutch), as the mu- prefix in this noun class were still pronounced, and was reported by Dutch visitors to Loango as referring both to a material item and the spiritual entity that inhabits it.