Notes: Since the root acquires the meaning 'to begin' or 'to end' in several subgroups, it seems possible to compare the Hurrian derivate al-ummi 'end; last' (see Diakonoff-Starostin 1986, 50).
The comparison seems quite plausible (see Абдоков 1983, 163; note also the existence of common EC and NC derivates meaning 'sheath, case' - see Абдоков 1983, 130). The final *-w has left traces in PA (*r-iƛobV), Lak. (Proto.-Lak. *ʎob(i) > Arch. ʎob) and PL (as labialisation of *-ʎ:ʷ-). In some languages, because of similar reflexes of *ƛ and *x, the root tends to be confused with PNC *-exE (q.v.), but they are opposed in several subgroups, and should be strictly distinguished.