An important set of sound changes affected the South Bantu languages (and a few other Bantu languages) through the impact of front vowels on following consonants, most notably under the form of the class 5 nominal prefix *i‑. For example, the class 5 word for ‘ember, charcoal’ has a different initial consonant (C1) from the class 6 stem in these singular/plural pairs: Chewa (N31) khala/ma‑kala, Manyika (S13) gara/ma‑kara, and Tsonga (S53) khálá/mà‑kálá. In some languages, however, differences between the singular and plural were later leveled to make consistent stems.
An -i- inside a stem could also cause a change on the following consonant, for example, Proto-Bantu *áítʊ ́ ‘our' > Chewa ‑athu, Venda ‑ashu, Karanga -edu, Gitonga ‑athu.
An -i- inside a stem could also cause a change on the following consonant, for example, Proto-Bantu *áítʊ ́ ‘our' > Chewa ‑athu, Venda ‑ashu, Karanga -edu, Gitonga ‑athu.
For details, see Wills, J. (2025). PI‑Effects in South Bantu: Consonant Changes Due to a Preceding Front Close Vowel. Languages, 10(2), 23. https://doi.org/10.3390/languages10020023