This PhD deals with the semantics of two major parts of the Bantu verbal system, namely derivation and tense/aspect, from a comparative and diachronic perspective. With respect to derivation, the aim of the PhD project is to relate a number of verbal affixes, which are found throughout Bantu, to the grammatical category of “middle voice”. With respect to tense/aspect, one aim of the PhD project is to present a first large-scale comparative overview of the most common tense/aspect constructions in the Kikongo Language Cluster from which i) Proto-Bantu retentions and ii) innovations from different stages in time can be identified. The isoglosses of the most common tense/aspect constructions can be confronted with the isoglosses of lexically-based phylogenetic subgroups, where both similarities and mismatches between the two provide relevant information about language history. A second aim of the study is to describe the diachrony of tense/aspect constructions and paradigms on the basis of different methods, such as the Comparative Method and/or Diachronic Corpus Linguistics.