PAT *(a)źǝ (cf. Bzyb. - in Marr's notation - á-ź); PAK (reduplicated) *zazǝ. Ub. -ca may be observed in c̣ʷa-cá 'gall' - assimilation from *c̣ʷa-zá (?); note that Ub. zaza 'gall' (recorded by Dirr), as well as Abaz. zaz (coexisting with the genuine az), is an Adygh loanword. The correspondence PAK, Ub. z : PAT *ź points to PWC *ž.
See Trubetzkoy 1930, 86; Шакрыл 1968, 25; Aбдоков 1973, 52; Шагиров 1977, 205.