This paper presents a comparative study of some food plant names in the Bantu languages of the Western Province of Zambia: millet (Pennisetum glaucum + Eleusine coracana), sorghum (Sorghum bicolor), maize (Zea mays), cassava (Manihot esculenta), and the (dwarf) mobola plum tree (Parinari curatellifolia/capensis). Some of these plants are indigenous and have been exploited for millennia. Others were introduced more recently. The variable distributional patterning of their lexical isoglosses informs us on the linguistic stratigraphy of the WP and illustrates how its current languages were originally divided by several linguistic frontiers, but have gradually integrated into a common linguistic area.