Notes: Both phonetically and semantically the etymology is quite satisfactory. As usual, in a root containing two stops there occur assimilations and dissimilations (PTs *kʷid < *kʷiṭ; PL *ḳurṭaj < *kurṭaj). The PWC form goes back rather to a form like *kɨ̄rṭwā (with shift of labialisation).
The only strange phenomenon is the uvular pharyngealized q̇I- in Lak. (and a similar form in Rut.); reasons for such a development are unclear, but it is hard to keep the Lak. and Rut. forms away from the rest.