√PHELEK or ᴹ√PHELEG “*cave”
An unglossed root with variants √PHELEK and √PHELES appearing in the margins for Notes on Names (NN) from 1957, as part of an exploration of the name S. Felagund (in this note given as Felegund or Felegond) and serving as the basis for the words Q. felco and S. feleg “cave” (PE17/118). Earlier in this 1957 note Tolkien gave the primitive form as ✶phelgā > Q. felya/S. fela “cave”, which is consistent with the derivative of the name N. Felagund in The Etymologies of the 1930s, which had the root ᴹ√PHELEG “cave” with derivatives ᴹQ. felya and N. fela of the same meaning (Ety/PHÉLEG). Later still, in the Shibboleth of Fëanor from 1968 Tolkien explained S. Felagund as an adaptation of the Khuzdul title Kh. Felakgundu “Cave-hewer” (PM/352). Thus it seems √PHELEG, √PHELEK and √PHELES were abandoned as Elvish roots.
Note that ᴹ√PHELEK also appeared in The Etymologies of the 1930s with the gloss “(animal’s) horn; steep mountain peak”, but that root was deleted (EtyAC/PHELÉK), perhaps replaced by ᴹ√TARAK of similar meaning.
Neo-Eldarin: For purposes of Neo-Eldarin, I think it is worth retaining the derivatives of ᴹ√PHELEG/✶phelgā, perhaps reimagined as loan-words from Khuzdul. I don’t think √PHELEK can be salvaged, though, as the name Felegund/Felegond never appears in the narratives; it was always Fela-.
The root ᴹ√PHEN first appeared (unglossed) in The Etymologies of the 1930s with derivatives like ᴹQ. fenda “threshold” and N. fenn “threshold, door” (Ety/PHEN). The root √PHEN “door” reappeared in etymological notes from 1959 as the basis for Q. fendë/S. fen “door” (PE17/181). The most notable name associated with this root was S. Fen Hollen “Closed Door” from The Lord of the Rings (LotR/826; RC/550) along with its precursors in LotR drafts: N. Fenn Forn(en) and N. Fenn Uiforn (WR/338, 341).
√PHILIK “finch, [ᴹ√] small bird”
This root first appeared as ᴹ√PHILIK “small bird” in The Etymologies of the 1930s with derivatives ᴹQ. filit and N. fileg of the same meaning (Ety/PHILIK). The root also appeared in the contemporaneous Primitive Quendian Structure: Final Consonants with an extra gloss “sparrow”, a deleted variant spilik-, and some additional (unglossed) derivatives ᴹQ. filinke and N. flinc (PE21/56). The root and these last two derivatives reappeared in Common Eldarin: Noun Structure from the early 1950s, in this document with the gloss “finch” (PE21/71-72, 80-81). Note that a likely early precursor to all these words was G. bilinc “sparrow, bird (small)” (GL/23).
√PHIN “clever, skillful; neat, fine, delicate; skill, dexterity, [ᴹ√] nimbleness”
This root has a long history in Tolkien’s Elvish languages, always having to do with clever and skillful things in association with the name Q. Finwë. It first appeared as unglossed ᴱ√FINI in the Qenya Lexicon of the 1910s with derivatives like ᴱQ. finie “cunning” and ᴱQ. finwa “acute, sagacious” (QL/38). It also had derivatives in the contemporaneous Gnomish Lexicon such as G. fim “clever; right hand”, G. fimlios “skillfulness”, and G. finthi “idea, notion” (GL/35). It reappeared in The Etymologies of the 1930s with the gloss “nimbleness, skill” and derivatives like ON. phinde “skill” and ON. phinya “skillful” (Ety/PHIN).
The root appeared a number of times in Tolkien’s later writings, as √PHIN- “skilful, neat, clever (especially applied to hands and fingers)” (PE17/17), √PHĪ/PHINI “skill, dexterity” (PE17/119), and √PHĬN “clever, fine, delicate” (PE17/119). In both The Etymologies and in later writings Tolkien made a point that this root was distinct from √SPIN from which various “hair” words were derived (Ety/PHIN; PE17/17), though in one place Tolkien gave that root also as √PHIN- (PM/340).
√PHIR “exhale, expire, breathe out; [ᴹ√] die of natural causes”
This root first appeared in The Etymologies of the 1930s as ᴹ√PHIR “die of natural causes” with derivatives like ᴹQ. fire/N. feir “mortal man” and ᴹQ. firin/N. fern “dead” (Ety/PHIR). In one place it had a rejected variant ᴹ√SPIR (EtyAC/ÑGUR). In later notes, Tolkien contrived a new meaning for √PHIRI as “exhale, expire, breathe out”, originally unconnected to death (WJ/387). In this new scenario, √PHIRI came to be associated with death through the passing of Q. Míriel, the most notable Elf to die of non-violent causes who “overcome by a great sorrow … gave up her life in the body and went to the keeping of Mandos, [with] a deep sigh of weariness” (WJ/387). In this event, she was given the new name Q. Fíriel “She that died” but also meaning “She that sighed” (MR/250). From there it came to be used of the natural death of mortal men, something which the Elves had little experience with themselves.
This root appeared as ᴹ√PHOR “right-hand” in The Etymologies of the 1930s with derivatives having to do with “right [vs. left]” and also “north” such ᴹQ. formen and N. forod “north” (Ety/PHOR). These words for “north” reappeared in The Lord of the Rings (LotR/1123), and the connection between “north” and “right” was reaffirmed in Tolkien’s discussion of the Ambidexters Sentence from the late 1960s, since the Elves aligned the cardinal directions by facing west towards Aman (VT49/6-8). ᴹ√PHOR was likely a later iteration of the early root ᴱ√PO from the Qenya Lexicon of the 1910s with various derivatives having to do with “north” (QL/74).
A root in The Etymologies of the 1930s with derivatives having to do with “night” such as ᴹQ. huine “deep shadow, nightshade” and N. fuin “night, dead of night” (Ety/PHUY). A similar root ᴱ√ǶUẎU appeared in the Qenya Lexicon of the 1910s with derivatives like ᴱQ. hui/G. fui “night” and G. fung “dark” (QL/41; GL/36). Tolkien noted that this early root must be “ƕ because of Noldo [Gnomish] fui” (QL/41). This is because ƕ [xʷ] > f universally in Gnomish but ƕu- > hu- in Early Quenya (PE12/17).
The 1930s forms likewise had a hu-/fu- variation between Quenya and Noldorin, because phu- > ꝑu- [ɸu] > hu- in Quenya. The continued appearance of Q. huinë and S. fuin from ancient ✶phuinē indicate the continued validity of this root in Tolkien’s later writing (PE17/120; PE19/71; RC/727).