Abstract Updating the methodology of Hayward, Richard J. 1991. A propos patterns of lexicalization in the Ethiopian language area. In Daniela Mendel & Ulrike Claudi (eds.), Ägypten im afroorientalischen Kontext. Special issue of Afrikanistische Arbeitspapiere , 139–156. Cologne: Institute of African Studies, using the concept of colexification (François, Alexandre. 2008. Semantic maps and the typology of colexification: Intertwining polysemous networks across languages. In Martine Vanhove (ed.), Studies in language companion series , vol. 106, 163–215. Amsterdam: John Benjamins), this paper, for the first time, provides quantitative evidence that the languages of the West African Sahel/Savanna form a lexical-typological language area characterised by shared colexifications absent further north. It then uses the linguistic comparative method to determine how languages entering or leaving this area, or coming into increasing contact with it at its edges, have converged with their new neighbours within the past millennium. The results indicate sharp differences in the respective roles and rates of borrowing and calquing, with the latter acting almost exclusively to increase shared colexifications.