COMMENT: face="Times New Roman Star" One of the most stable and widely spread NC kinship terms with changing class prefixes. It is also preserved in HU, cf. Hurr.
s?e-ni 'brother' (despite another etymology given in Diakonoff-Starostin 1986, 43, the word most probably belongs here).
Two basic original forms must be reconstructed as *u_-y>c/_i>(jV) 'brother' (with frequent further development > *c/_wy>jV or *c/_wi>jV; exactly this form is reflected, e.g., in PL and PWC), and *j-y>c/_i>(jV) 'sister' (sometimes with a similar contraction > *c/_i>jV). The arisal of the new feminine class prefix *r- in the Eastern area led to a new formation *r-y>c/_i>(jV) 'sister', reflected in Darg., Khin. and part of Lezghian languages.
See Trubetzkoy 1930, 278, Rogava 1956, Balkarov 1969, Shagirov 1, Abdokov 1983, 87. Despite Charaya 1912 and Yakovlev 1941, Kartvelian words for 'brother' (Megr. z?|ima, Georg. z|ma) and 'son' (s?wili) have nothing to do with PNC *=y>c/_i>.