The root √ANGWA “snake” with variant √ANGU appeared in The Etymologies of the 1930s as the basis for the words ᴹQ. ango “snake” (Ety/ANGWA) and angulóke “dragon” (Ety/LOK). The Noldorin equivalent am- seems to have survived only as a prefix (Ety/ANGWA), and is a good example of how [[on|[ŋgw] > [mb]]] in that language. There are a variety of other words for “snake” in Tolkien’s later writings, so whether this root remained valid is unclear.
Middle Primitive Elvish
liñwi
noun. fish
lingi
root. hang
(g)lingi
root. hang
angwa
root. snake
pheleg
root. cave
rǭda
noun. cave
skala
noun. fish
A root in The Etymologies of the 1930s glossed “hang” and acting as an alternate explanation of ᴹQ. Laurelin, usually interpreted as “Song of Gold” but also meaning “Hanging Flame” as reflected in its Noldorin name Glingal (Ety/GLING, LIN², LING). The continued appearance of S. Glingal in later versions of The Silmarillion indicates this root likely remained valid (S/126).
A pair of forms ᴱQ. kinka- “to hang (intr.)” and ᴱQ. kinkata- “hang (tr.)” in the Qenya Lexicon of the 1910s imply the existence of a root ᴱ√KINIKI, which may be a precursor to ᴹ√(G)LINGI.