Proto-Eastern Bantu is the reconstruction of the latest common stage (aka "the most recent ancestor") for all languages in zones EFGJMNPS (as well as K21 and many in zone D), i.e., node 10 on the Bantu time consensus tree in Grollemund et al. (2015), cf. Koile et al. (2022). For our purposes, that is more than enough material for stable reconstructions. South Bantu consists of clades 16 and 17 on the tree of Koile et al. (2022). See the charts in Bantu language groups.