Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
gioth
noun. germ, foetus, embryon
giothra-
verb. to germinate, be conceived
A word appearing as G. giothra- “germinate, be conceived” in the Gnomish Lexicon, a verb form of G. gioth “embryo” from the early root ᴱ√giu̯i (GL/39).
Neo-Sindarin: I would update this word to Neo-Sindarin ᴺS. gythra-, verb form of updated ᴺS. gŷth, based on the later sound change whereby iu > ȳ.
giothrin
adjective. embryonic
A word appearing as G. giothrin “embryonic” in the Gnomish Lexicon, an adjectival form of G. gioth “embryo” from the early root ᴱ√giu̯i (GL/39).
Neo-Sindarin: I would update this word to Neo-Sindarin ᴺS. gythren, adjectival form of updated ᴺS. gŷth, based on the later sound change whereby iu > ȳ.
giwth
noun. germ, foetus, embryon
A noun appearing as G. gioth or giwth “germ, foetus, embryon” in the Gnomish Lexicon of the 1910s derived from the early root ᴱ√giu̯i [GIWI] which was the basis for a number of words having to do with pregnancy (GL/39), where iu to io as usual in Gnomish.
Neo-Sindarin: I would adapt this word into Neo-Sindarin as ᴺS. gŷth, using the later sound change whereby iu > ȳ.