This root was given as ᴱ√MASA¹ “dusk” in its main entry in the Qenya Lexicon of the 1910s, but its Gnomish form math- indicates the true root was ᴱ√MAÞA (QL/59). This was clarified in a list of roots at the end of the M-section in the Qenya Lexicon (QL/63) and its representation as maþ- in the contemporaneous Gnomish Lexicon (GL/59). Its most notable use in the Legendarium was in the name G. Umboth-muilin “Pools (muil-plural) of Twilight (umboth)”, where G. umboth or umbath “nightfall” was derived from a strengthened form of the root, ᴱ√mbaþ- (GL/75). However, in later writings this name was reconceived as Ilk. Umboth Muilin “Veiled (muilin) Pool (umboth)”, with the first element umboth meaning “large pool” (Ety/MBOTH, MUY). The name was ultimately replaced with S. Aelin-uial (S/114), by which point the early root ᴱ√MAÞA was long abandoned.
Early Primitive Elvish
usu
root. get out, escape
ʒuðu Reconstructed
root. *burn
-yǝ
suffix. [unglossed]
lepse
?. [unglossed]
lopse
?. [unglossed]
maþa
root. dusk
saw̯a
root. [unglossed]
An unglossed root in the Qenya Lexicon of the 1910s (QL/82), which may have reemerged as √SAWA “disgusting, foul, vile” in notes from the 1950s (PE17/172, 183).
sivi
root. [unglossed]
Unglossed roots in the Qenya Lexicon of the 1910s with variants ᴱ√SIVI and ᴱ√SIWI and a single unglossed derivative ᴱQ. sivilda (QL/84). It is difficult to guess what Tolkien intended for these forms to mean, though they conceivably reemerged as the later roots ᴹ√SIW “excite, egg on, urge” (Ety/SIW) or √SIB “rest, quiet” (VT44/35).
teled-
noun. [unglossed]
tołᵂo
root. [unglossed]
An unglossed root in The Qenya Phonology of the 1910s illustrating a hypothetical series of ancient lateral approximants, with derived roots like ᴱ√TOLO and ᴱ√TOẆO [with ẇ = ɣʷ] (PE12/16). The former appeared in the contemporaneous Qenya Lexicon as the basis for island words (QL/94), but the latter appeared nowhere else in Early Qenya writings.
toẇo
root. [unglossed]
tḷkḷ
root. [unglossed]
vo(no) Reconstructed
root. son
The root ᴱ√USU⁽⁾ appeared in the Qenya Lexicon of the 1910s with the gloss “get out, escape” and derivatives like ᴱQ. usu- “he escapes” and ᴱQ. uswe “issue, outlet, escape” (QL/98). In the contemporaneous Gnomish Lexicon it had derivatives like G. us(ta)- “leave, depart” and G. uthwen “way out, exit; escape” (GL/75), the latter hinting that the root form may have been a blending with ✱ᴱ√UÞU. I think it is worth positing a Neo-Eldarin root ᴺ√UTH to salvage these early words for “escape”.