Where does “ngâ” come from?

ngâ (Namuyi) comes from Proto-Sino-Tibetan ŋa, from Proto-Sino-Tibetan l/b-ŋa — five.

Ancestry of “ngâ”, step by step

Step	Language	Word	Meaning
1	Proto-Sino-Tibetan	ŋa	I
2	Proto-Sino-Tibetan	l/b-ŋa	five

ngâ — Etymology, Origin & Word History | Etymology Explorer