The basis for Elvish “tree” words, this root first appeared in The Etymologies of the 1930s as an extension of ᴹ√GALA “thrive” (Ety/GALAD). This replaced the earliest derivation of “tree” from the Qenya Lexicon of the 1910s, where the Qenya word for “tree” ᴱQ. alda was derived from ᴱ√ALA “spread” (QL/29). In The Etymologies, the Quenya form of this word remained the same, but the 1910s Gnomish words G. âl “wood” and †alwen “tree” (GL/19) became the 1930s Noldorin word N. galadh “tree” (Ety/GALA). Quenya and Sindarin retained these words for “tree” thereafter, and while Tolkien did not mention the root √GALAD again, his continued use of primitive ✶galadā “tree” (Let/426; PE17/153; PE21/74; UT/266) made it clear this root remained valid.
Middle Primitive Elvish
lam
root. *sound
lamanǝ
noun. lamanǝ
lambe
noun. lambe
nay
root. lament
nāyǝ
noun. lament
angwa
root. snake
gaisrā
adjective. dreadful
galad
root. tree
galadā
noun. tree
gālæ
noun. light
kalat
noun. light
k’lā
noun. light
om
root. *sound
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.