Where does “tiangelo” come from?

tiangelo (Chichewa) comes from Chichewa ti-, from Proto-Bantu *tʊ̀-.

Ancestry of “tiangelo”, step by step

Step	Language	Word	Meaning
1	Chichewa	ti-	1st person plural subject concord, we
2	Proto-Bantu	*tʊ̀-	—