As with many adjectival stems, the root is frequently reduplicated. EC and WC languages reflect both the simple and the reduplicated stem. In some subgroups (particularly, in Lezghian) the root was subject to complicated expressive transformations, but still the semantic and phonetic unity of the listed forms is beyond doubt.

    Besides *Hamq̇ʷV, Lezgian languages have a series of phonetically close forms with *-q̇:(ʷ)- and *-q:-: Tab. Düb. c-uq:i, Ag. q:uq:u-f (Burk. q:uq:u-f) 'hard', Lezg. weq:i 'rigid, rough', quq:ʷa-z 'to become rigid, to harden' (Khl. qʷq:ʷaj 'hard' = lit. quq:ʷaj 'hardened'), Rut. Mukh. (Ibragimov) ʁiʁ-dɨ 'hard, tough', Luch. q-u=ʁʷa- 'to harden, dry out' ( = Lezg. quq:ʷa-), ʁIɨʁI-dɨ 'hard'. It is rather hard to reconstruct a single protoform for all these forms: we probably deal both with expressive modifications of PL *Hamq̇ʷV and with assimilative developments of the reduplicated form *q̇Vmq:V (from the PEC variant *q̇Hwamq̇_(w)Ă).