Conférence de Rebecca Grollemund : Bantu population dispersal throughout Africa shows preference for routes following familiar habitats (9h30-10h45)
The Bantu language family has the largest geographical area of any in Africa, with approximately 240 million speakers divided among 400-600 languages spoken across 27 countries. It is now widely accepted that the Bantu expansion began approximately 5000 years ago, somewhere around the Nigerian-Cameroonian borderland, eventually moving all the way to present day South Africa, but the precise routes and the timings of those routes are still debated.
To investigate these questions, we propose a new phylogenetic classification of Bantu languages. Our study is based on an analysis of 100 words belonging to the basic vocabulary documented in 424 Bantu languages, and covering the entire Bantu-speaking area (zones A, B, C, D, E, F, G, H, J, K, L, M, N, P, R and S). We infer the tree using a likelihood model of lexical evolution (allowing different rates of evolution for the words studied) implemented in a Bayesian Markov chain Monte Carlo (MCMC) approach. We employ ‘relaxed clock’ dating methods, which produce a topology and date estimates for all nodes of the tree.
This approach allows us to obtain the first dated phylogenetic classification of the Bantu languages. Using the tree in conjunction with present day geographical information we infer a novel dispersal route for the Bantu language family showing that the Bantu expansion exploited savannah corridors that opened up through the Congolian rainforest beginning around 4000BP. Our results show that changes of the rainforest favoured the Bantu migration and that the migrating Bantu populations did not follow a ‘random walk’ but showed measureable preferences for following savannah routes.
Conférence de Koen Bostoen : Archaeo-linguistic perspectives on Bantu language and population dynamics in the Lower Congo region of Central-Africa (11h00-12h15)
The wider Lower Congo region of Central-Africa is home to the so-called ‘Kikongo language cluster (KLC)’, a disparate continuum of closely related Bantu languages that spread over large parts of four neighbouring countries, i.e. Angola including Cabinda, the Democratic Republic of the Congo (DRC), the Republic of the Congo and Gabon. Recent phylogenetic research has corroborated that this vast language group constitutes a discrete clade within Western Bantu and that its centre of expansion is most likely situated to the north-east of the Lower Congo region (de Schryver et al. 2015 (forthcoming)). A recent interdisciplinary review of evidence from biogeography, palynology, geology, historical linguistics and archaeology has in its turn pointed out that a climate-induced opening of the Central-African forest block around 2500 BP – and not agriculture as is widely believed – was probably responsible for the rapid southward expansion of Bantu speech communities across the Equator (Bostoen et al. 2015). It favoured, among other things, the introduction of Bantu languages into the area north of the Malebo Pool on the Congo River in the approximate vicinity of the Batéké plateau, from where speakers of the KLC’s most common recent ancestor may have started to spread further west.
This tentative location of the KLC homeland to the north-east of the Lower Congo region is difficult to test archaeologically due to the paucity of excavations in that specific area. Moreover, it seems at odds with the currently available archaeological evidence within the Lower Congo area itself. In this paper, we have a closer look at the matches and mismatches between the linguistics and archaeology and what they tell on the expansion of early Bantu speech communities in the Lower Congo region.
We also consider how the earliest ceramic traditions relate to subsequent ceramic traditions and to which extent this can be correlated with evolution of language in the Lower Congo region. While no other language group than the KLC is present in the Lower Congo region, its ceramic sequence since 2700 BP clearly testifies to several clear-cut ruptures. If not with the spread of Bantu languages or the settlement of new Bantu speech communities, it remains to be established with which kind of historical developments these significant innovations in the ceramic production of the Lower Congo region can be linked. Phenomena such as political centralization, elite formation and economic integration certainly had an impact on the evolution of both language and material culture in this area which hosted the emblematic kingdom of the Kongo as well as several closely related polities and was pivotal in both regional and international trade networks. This makes the Lower Congo region a challenging area for archaeo-linguistic studies, such as those carried out by the KongoKing research group (see http://www.kongoking.org).
References
Bostoen, Koen, Bernard Clist, Charles Doumenge, Rebecca Grollemund, Jean-Marie Hombert, Joseph Koni Muluwa, and Jean Maley. 2015. Middle to Late Holocene Paleoclimatic Change and the Early Bantu Expansion in the Rain Forests of West Central-Africa. Current Anthropology 56 (3).
Clist, Bernard. 2005. Des premiers villages aux premiers européens autour de l'estuaire du Gabon : quatre millénaires d'interactions entre l'homme et son milieu. Thèse de doctorat, Université libre de Bruxelles, Bruxelles.
de Maret, Pierre. 1986. The Ngovo Group: an Industry with Polished Stone Tools and Pottery in Lower-Zaïre. African Archaeological Review 4:103-133.
de Schryver, Gilles-Maurice, Rebecca Grollemund, Simon Branford, and Koen Bostoen. 2015 (forthcoming). Introducing a state-of-the-art phylogenetic classification of the Kikongo language cluster. Submitted for publication in Africana Linguistica 21.
Denbow, James. 2012. Pride, Prejudice, Plunder, and Preservation: Archaeology and the Re-envisioning of Ethnogenesis on the Loango coast of the Republic of Congo. Antiquity 86 (332):383-408.
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Développement, Neurocognition, Dysfonctionnements
Diversité Linguistique et ses Sources
