Comments: PAK *nač̣́ǝ́. See Aбдоков 1973, 61, Шагиров 1977, 282. Somewhat uncertain is the status of the first syllable. It can be either reconstructed as *wṼ (with *w- possibly reflecting the old class prefixation), or Shagirov may be right in treating PAK *na- and Ub. wǝ- here as two different derivational morphemes.
Comments: PAK *xá-tǝ. Abdokov (1973, 23, 72) and Shagirov (2, 104) are quite right in comparing this morpheme with Ub. š́ǝ and rejecting Trubetzkoy's (1930, 80) comparison of Ub. š́ǝ with Bzhed., Shaps. śǝ-d 'what'. Semantically and phonetically the comparison š́ǝ = AK *xa- is blameless.
Comments: PAT *x́ǝ is attested both separately (Abaz. χ́-ra 'get cold, cool down') and within compounds (PAT *χ́ǝ-ta 'cold (n.)' > Abkh. á-χ́ta, Abaz. χ́ta,*χ́ǝ-sʷasʷa 'cold (adj.)' (with an unclear second component), *ʒǝ-χ́ǝ 'cold water, spring' (Abkh. a-ʒǝ́χ́, Abaz. ʒǝχ́).
PAK *š́ǝtǝ- = PAT *x́ǝ-ta. Abdokov (1983, 104) attempts to relate the PAT root (separated from PAK) to Arch. χIe- 'cold'; this is obviously impossible (the Archi form, along with a number of other EC reflexes, goes back to PEC and PNC *=HĭGĀ q.v.).
Comments: PAT *xǝ (cf. also Bzyb. a-x-rá); PAK *xǝ- (trans.), *xa- (intrans.: Ad., Kab. xa-n); Ub. sing. a-s-š́ǝ́-n. The same root was used in PWC with the meaning 'saw, to saw', cf. PAT *xǝ- (Abkh. a-χ-rá, Abaz. ʕʷǝ-χ-ra 'to saw'), PAK *pǝ-xǝ- 'to saw' (Ad., Kab. pǝxǝ-),*pχá-xǝ 'saw' (Ad., Kab. pχax;*pχa 'tree, wood'), Ub. sǝ-š́ǝ́ 'saw' (sǝ 'wood').
Despite Yakovlev 1941, 209-210, there is absolutely no connection with PAK *-xǝ- 'to take'. See Shagirov 2, 105, 40 (but PAK *pǝxǝ- 'to saw' should be distinguished from the homonymous *pǝxǝ- 'to take off (from the front of smth.)', which has a quite different WC etymology).
Comments: PAT *-xa- (Bzyb. -xa-), used in compound verbs (cf. Abkh. a-pśa-rá 'to have a price' - a-pśa-xa-rá 'to become a price'; Abaz. bargʷǝ 'difficult' - bargʷ-χa-ra 'to become difficult' etc.; in Abaz. there occurs also a variant -χ(ǝ)-, cf. bá-χ-ra 'to dry, become dry' etc.). Ub. sǝ-š́ǝ́-n.
Shagirov (1,280;2,108) compares (with some doubt) Ub. š́ǝ- with PAK *śǝ- (apparently used in some compounds with the meaning 'to become'), but concedes himself that phonetically such a comparison is impossible. Despite Dumézil 1938, 74 and Shagirov 2, 113, PAT *-xa- can not be related to PAK *χʷǝ- 'to become' (for phonetic reasons).
Comments: PAT *xʷa (cf. also Bz. á-xʷa). In Ub. -ḳ́ǝ is an archaic singulative suffix; the morpheme xa- by itself is used in compounds. In Adygh cf. perhaps Kab. xʷǝ-ps 'larva, grub'.
Comments: PAT *xʷa in compounds with *š́a 'foot, leg' and *ma 'hand, arm': *š́a-xʷa > Abkh. a-š́a-χʷá 'marrow', a-š́a-χʷá-r 'metatarsus', Bzyb. a-š́a-xʷá-r 'metatarsus, marrow in metatarsus bone; leg (from pelvis to knee)'; *ma-xʷa > Bzyb. a-ma-xʷá-r 'arm (from elbow to hand)'. The meaning of *xʷa may be reconstructed as "bone from one joint to another" < "joint" < "sinew". PAK *xʷa.