Comments: PTsKh *ʔüR- / *güR- (the reason for loss of g- in Tsez. is not clear); PGB *g=ǝl-. All forms (except Bezht.) are taken from Bok. Tsez. In PGB the verb retains class markers (despite the loss of initial vowel), which interact with the root vowel (*gǝl- / *gil- / *gul-).