Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Bostoen, Koen; de Schryver, Gilles-Maurice (2018). "Seventeenth-century Kikongo is not the ancestor of present-day Kikongo". In Bostoen, Koen; Brinkman, Inge (eds.). The Kongo kingdom: the origins, dynamics and cosmopolitan culture of an African polity. Cambridge: Cambridge University Press. pp. 60–102.
Bostoen, Koen; de Schryver, Gilles-Maurice (2018). "Langues et évolution linguistique dans le royaume et l'aire kongo". In Clist, Bernard-Olivier; de Maret, Pierre; Bostoen, Koen (eds.). Une archéologie des provinces septentrionales du royaume Kongo. Oxford: Archaeopress. pp. 51–55.
Pacchiarotti, Sara; Chousou-Polydouri, Natalia; Bostoen, Koen (2019). "Untangling the West-Coastal Bantu mess: identification, geography and phylogeny of the Bantu B50-80 languages". Africana Linguistica. 21: 87–162.
Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2017). "KLC Extended". Glottolog 3.0. Jena, Germany: Max Planck Institute for the Science of Human History.