Where does “ไห้” come from?

ไห้ (Thai) comes from Proto-Tai *t.hajꟲ.

ไห้ (Thai): to cry; to weep; to wail

Definitions

Step	Language	Word	Meaning
1	Proto-Tai	*t.hajꟲ	—

ไห้ — Etymology, Origin & Word History | Etymology Explorer