Notes: A universal onomatopoeic root (cf. Engl. cuckoo, Rus. кукушка, PK *gugul etc.); because of its expressive nature it is hard to make a precise reconstruction. We may note, however, that two basic variants (with *g and with *ḳ) are predominant in most languages. It is also interesting that some expressive suffixes seem to occur in several groups; cf. notably Bacb. gugu-ṭṭ, PGB *kuku-ṭo / *ḳuḳu-ṭo, Darg. gegu-t, Bud. gugu-ṭ. See Abdokov 1983, 117.
