Since PAK *č́ = Ub. č́ and PAK *x = Ub. šʷ, it seems very probable to compare the words in whole (assuming a metathesis in one of the subgroups). The PAT form *č́č́a can be easily explained as a result of assimilation < *šǝč́a (where *š < *ʎ́ʷ and *č́ < *č́). Therefore the commonly accepted comparison of Abkh. -č́č́a- with PK *cc- 'to laugh' (Charaya 1912, 48, Shagirov ibid etc.) seems rather superficial. If PWC *ʎ́ʷV-č́V- (*č́V-ʎ́ʷV) is a compound verb, only its component *č́V can be compared with Kartvelian (we should add that both forms are probably onomatopeic in origin); the component *ʎ́ʷV is certainly related to EC forms meaning 'to laugh'.