Where does “*zaːjᴬ⁴” come from?

*zaːjᴬ⁴ (Proto-Southwestern Tai) comes from Proto-Tai zwɯəjᴬ, from Old Chinese 沙.

Ancestry of “*zaːjᴬ⁴”, step by step

Step	Language	Word	Meaning
1	Proto-Tai	zwɯəjᴬ	sand
2	Old Chinese	沙	—

*zaːjᴬ⁴ — Etymology, Origin & Word History | Etymology Explorer