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
son
root. love, befriend, cherish
yo(n)
root. son
yondō
noun. son
sel(d)
root. child, child; *daughter
galadā
noun. tree
galad
root. tree
kwentā
noun. tale
lak
root. swallow
A root in The Etymologies of the 1930s glossed “swallow” with variant ᴹ√LANK and derivatives ᴹQ. lanko/N. lhanc “throat” (Ety/LAK¹, LANK), the latter an element in N. tarlanc “stiff-necked, obstinate” (Ety/TÁRAG). This last word was changed to S. tarlang in Tolkien’s later writings (PE17/92; RC/536), consistent with an earlier but rejected form ᴹ√LANG for ᴹ√LANK in The Etymologies (Ety/LANK).
In later writings, Q. lango/S. lang meant “neck” rather than “throat”, so it is tempting to retain ᴹ√LAK for “throat” and other swallow-words. But it would be very confusing to have such similar but unrelated words for “neck” and “throat”, so I recommend using the root ᴹ√SLUK for “swallow” instead, and Q. lango, S. lang for both “neck” and “throat”.
lank
root. swallow
mālō
noun. friend
sluk
root. swallow
A root in The Etymologies of the 1930s with no derivatives (Ety/SLUK).
wis
root. air
yel
root. friend
A root in The Etymologies of the 1930s, initially glossed “daughter” but later “child” with derivatives ᴹQ. selde, ᴹQ. seldo, ᴹQ. selda = female, male and neuter “child” (Ety/SEL-D). In Notes on Names (NN) from 1957 Tolkien gave sel-de “daughter” (PE17/170), while S. sel(l) = “daughter” appeared in both the King’s Letter from the late 1940s (SD/129) as well as the Túrin Wrapper from the 1950s (VT50/5). The diminutive form for “daughter” appeared as Q. selyë in notes from the late 1960s (VT47/10).
Neo-Eldarin: For purposes of Neo-Eldarin, I prefer √YEL for “daughter” as a variant of ᴹ√SEL(D) under the influence of √YON “son”, mostly so I can still use the 1930s “child” words for other genders, at least in the Quenya branch. I would still use Q. seldë and S. sell for “daughter”, however, with a bit of semantic drift, with “girl” words becoming Q. nettë and S. neth.