A noun appearing as G. gogel “mouth” in The Gnomish Grammar (GG/8) and as {gogel >} gogíl or gogail “mouth” in the Gnomish Lexicon of the 1910s (GL/40). In the latter document, Tolkien said it was a combination of G. go- “together” and G. cail “lip”, from more archaic forms gwa-caíl, gwa-cil. An unrelated word G. mem “mouth” also appeared in Gnomish Lexicon (GL/57), perhaps related to G. beg “chin” which Tolkien connected to ᴱQ. pé “(closed) mouth” = “the two lips” (GL/57; QL/72).

Neo-Sindarin: I’ve used these Gnomish words as the inspiration for a neologism ᴺS. gobem “mouth”, based on the (neologism) ᴺS. pemp “lip”, where the reduction of -mp to -m finally is an irregular assimilation to the preceding voiced b: -mp > -mb > -m.