Where does “chimwana” come from?

chimwana (Chichewa) comes from Chichewa chi-, from Proto-Bantu kɪ̀- — Class 7 noun prefix.

Ancestry of “chimwana”, step by step

Step	Language	Word	Meaning
1	Chichewa	chi-	language prefix; language
2	Proto-Bantu	kɪ̀-	Class 7 noun prefix