Comments: PAT *-ṗǝ is used as a common suffixed root denoting present tense of static verbs and future tense of dynamic verbs. Glottalisation is here probably secondary - because of standard reduction of final -ǝ and neutralisation of laryngeal features in final position. Ub. -tʷ(ǝ)- is a general verbal root ('to be, to be there') used with all kinds of preverbs.
In AK we would expect *-t- to correspond to Ub. tʷ; it seems probable that the two general PWC verbal roots, *tV and *ṕǝ, merged in PAK *tǝ- (see *tV).