A root mentioned in passing in Common Eldarin: Noun Structure from the early 1950s as √SATHA “pair” (PE21/74). It had no derivatives in that document, but might be connected to ᴱQ. satto “both” from the 1910s (PE14/76-77) and Ad. satta “two” from the 1940s (SD/428). In the 1950s document, Tolkien wrote in the margin “Best get rid of s, th [for duals] ?”, indicating he likely abandoned √SATHA.
Primitive elvish
sat
root. space, place; divide, apportion, mark off
sath
root. pair
sat(ar)
root. faithful, trust, loyal, rely, steadfast
satarŏ
noun. trusty follower, loyal companion
satrā
adjective. steadfast, trusty, loyal
satya-
verb. set aside
(a)tata
cardinal. two
atata
root. two, two; [ᴹ√] again, back
atta
cardinal. two
ekka
noun. hole
kayan
root. ten
khamu-
verb. to sit down
kuldā
adjective. hollow
kway
root. ten
A root Tolkien introduced in the late 1960s as the basis for his latest Elvish word for “ten”: Q. quëan/quain, S. pae, T. pai(n) (VT42/24; VT48/6). It was an extension of √KWA “complete” as in “a complete set of (10) fingers”. Prior this late change, the usual word for “ten” was ᴹQ. kainen (along with other variants beginning with kai- or kea-) from the root ᴹ√KAYAN or ᴹ√KAYAR as it appeared in The Etymologies of the 1930s (Ety/KAYAN). This basis for “ten” dates back to the Early Qenya Grammar of the 1920s (PE14/49, PE14/82). Tolkien was still considering √KAYAN for “10” in the late 1960s before replacing it with √KWAY(AM) (VT48/12).
kwayam
cardinal. 10
nābā
noun. hollow
stor
root. steadfast
A root appearing Notes on Names (NN) from 1957 serving as an explanation for the element S. thorn “steadfast” in the name S. Arathorn, first appearing in a rejected page with variants √STOR and √THOR (PE17/113-114) and then later as only √THOR (PE17/113). This root may be connected to Q. torna “hard” in notes on Quenya intensive forms written between the first and second edition of The Lord of the Rings, where it was an element in Q. tornanga “hard iron”, with intensive forms aristorna, anastorna that imply derivation from √STOR (PE17/56).
Neo-Eldarin: For purposes of Neo-Eldarin, I would assume this root is √STOR to avoid conflict with ᴹ√THOR(ON), the basis for “eagle” words.
tata
masculine name. Two
thor
root. steadfast
yu
root. both, both, [ᴹ√] two
This Elvish root was connected to the sense “two” or “both” throughout Tolkien’s life. The first clear manifestation of this root was ᴱQ. yú “twice” and ᴱQ. yúyo “two” from the Early Qenya Grammar of the 1920s (PE14/49-51, 82-84). The root ᴹ√YŪ “two, both” appeared in The Etymologies of the 1930s with derivatives like ᴹQ. yúyo “both” and ᴹQ. yúkale/N. uial “twilight” (Ety/KAL, YŪ). The root √YU appeared several times in Tolkien’s later writings, generally with the sense “both” (PE17/70; PE21/74; VT48/8, 10). It was likely related to the ancient dual suffix ✶-ū.
yŭ
conjunction. both
The root √SAT appeared in notes on The Rivers and Beacon-hills of Gondor from the late 1960s glossed “space, place, a limited area naturally or artificially defined” with various derivatives like Q. sati-/S. seidia- “set aside, appropriate to a special purpose or owner”, Q. satya/S. said “private, separate, not common, excluded”, and S. sad “place, spot” (VT42/19-20). The same root appeared in notes on fractions from 1968 with the gloss “divide, apportion”. It was likely also connected to the primitive suffix ✶-stā ( PE18/35; PE21/57, 82) that was the basis for the Sindarin/Noldorin collective suffix -ath, as well as the Quenya suffix Q. -sta often seen in place names like the regions of Númenor, and apparently meaning “any particular arrangement, grouping or collection [of things]” (VT39/16, 20 note #27).
A possible early precursor is the (hypothetical) root ᴱ√SATA needed to explain words in Gnomish Lexicon of the 1910s such as G. sad- “reck, care, value, esteem, show respect for, consider” and G. sâd “riches, wealth” (GL/66), but the apparent meaning “✱value” is far removed from the later meaning of the root √SAT = “space; apportion”. There was, however, another root √SAT(AR) Quenya Notes (QN) from 1957 with the gloss “faithful, trust, loyal, rely, steadfast” and derivatives like Q. astar/S. astor “faith, loyalty” and Q. satar/S. sadron “trusty follower, loyal companion” (PE17/183), the last appearing as an element in the name S. Echad i Sedryn “Camp of the Faithful” (UT/153). This 1957 root is a bit closer in meaning to ᴱ√SATA “✱value”, though still not an exact match.
Neo-Eldarin: For purposes of Neo-Eldarin, I would assume √SAT = “space; apportion” and unrelated √SATAR = “faithful, loyal”.