Someone or an animal's teeth (ma-) can gnaw though something tough, a tool can cut through something tough.
ngatngat
Manget kwabaw karniaya.
(My teeth) can not gnaw through the meat.
Nanget aba no bahayang bodayaya, ta matwa.
The bolo can not cut through the python, because it is tough.
Someone or an animal's teeth (may-, mang-) tears off and gnaws on something tough (-en).
must be reduplicated
ngetngét, ngutngót
ngatngat, nguya
Mayngetnget chitos lalat.
The dog('s teeth) tears off and gnaws on the hide.
ngaletnget
The sound of someone or an animal grinding his/its teeth.