This PhD thesis consists of the documentation, reconstruction and classfication of ten Bantu languages (bolondo , bonyange, ebudzà , ebwela, lib bi, ling mb , mond ng , mony ng , mos ngé, pagabéte) spoken in the geographical area between the Congo and Ubangi Rivers in the north- western part of the Democratic Republic of the Congo. The study examines the interaction between these languages and seven neighboring Ubangian languages (gb nz r , g b , ma , mb nz , monz mb , ngbandi, ngbaka-m n gend ). By means of a lexicostatistical study which determines the degree of lexical similarity between the languages under study, a phylogenetic classi cation has been established which integrates these languages in the larger sample of 401 Bantu languages used by Grollemund et al. (2015). This quantitative approach has generated Neighbor-Net and Neighbor-Joining networks as well as Bayesian trees, which indicate the in- ternal sub-groups of the Bantu family in general, and more speci cally of the Bantu languages of the central Congo basin to which the Bantu languages spoken between the Congo and Ubangi Rivers belong. Subsequently, we have undertaken a descriptive and comparative study of the those languages as well as a study of regular sound correspondances with regard to Proto-Bantu. They possess certain foreign phonemes that have not been reconstructed to Proto-Bantu, such as im- plosives and labiovelar stops, which have the status of distinct phonemes. The study of these spe- ci c sounds suggests that they were borrowed from the neighboring Ubangian languages. The lexical comparison also revealed an interaction between Bantu and Ubangian languages. Certain lexical borrowings were transferred from Bantu to Ubangian, while others moved in the opposite direction. Through the comparative method, we have obtained a phonological reconstruction of the hypothetical ancestor language of these langues. This Proto-Congo-Ubangi Bantu split into two sub-branches, i.e. Proto-Congo Bantu and Proto-Ubangi Bantu.