Where does “ຫ້າສິບ” come from?

ຫ້າສິບ (Lao) comes from Lao ຫ້າ, from Proto-Tai *haːꟲ, from Old Chinese 五.

ຫ້າສິບ (Lao): fifty

Definitions

Step	Language	Word	Meaning
1	Lao	ຫ້າ	five
2	Proto-Tai	*haːꟲ	—
3	Old Chinese	五	—

ຫ້າສິບ — Etymology, Origin & Word History | Etymology Explorer