Just out of the blue: What could be the etymology, if there is at all, of sgo nga “egg”? Interestingly egg is alo called “bird-fruit” (bya ’bras). Kun-bzang-rnam-rgyal, Ngag sgron yang ’grel (p. 244). It can well be derived from the verb sgong ba (Jäschke 1881: s.v.) “to make round, globular” and hence “something that is oval.” Possibly sgong ba also means “to coagulate” and hence egg is “something that has assumed a solid or semisolid state.” Just a food for thought. So please do not assume these to be positions etched in the rocks of time.