Where does “-taːlʔ” come from?

-taːlʔ (Proto-Vietic) comes from Proto-Mon-Khmer kt₁aal — under-surface, under.

Ancestry of “-taːlʔ”, step by step

Step	Language	Word	Meaning
1	Proto-Mon-Khmer	kt₁aal	under-surface, under

-taːlʔ — Etymology, Origin & Word History | Etymology Explorer