√RĪ “*edge, border”
An unglossed root in The Etymologies of the 1930s with derivatives like ᴹQ. ríma “edge, hem, border” and N. rhîf “brink, brim” (Ety/RĪ). Tolkien then added a note “alter to SRI-” without revising the derivatives (EtyAC/RĪ). Given that all its derivatives indicate primitive rīm-, it is almost certainly a later iteration of the unglossed root ᴱ√RIMI from the Qenya Lexicon of the 1910s with derivatives like ᴱQ. rim- “border on, lie at edge, neighbour” and ᴱQ. rímen “border, shore”, given in the same entry with the root ᴱ√RIPI with which it was apparently confused (QL/80). ᴱ√RIMI likewise had derivatives in the contemporaneous Gnomish Lexicon such as G. rim “a stripe, line; border, fringe” (GL/65), though blending with ᴱ√RIPI complicates the analysis; see that entry for further details.
√RIG “wreath, twine; garland, crown”
This root first appeared as unglossed ᴹ√RIG in The Etymologies of the 1930s with derivatives like ᴹQ. ríe/N. rhî “crown” and ᴹQ. rína/N. rhîn “crowned” (Ety/RIG). The root was then altered to ᴹ√RIƷ (EtyAC/RĪ). A similar root √RIK with derivation ✶riknā >> Q. rína (all unglossed) appeared in the first layer of composition for the Outline of Phonology from the early 1950s, but this section was revised in green ink around 1970 and the root did not appear in the revisions (PE19/85-86 and note #79). The root √RIG appeared a number of times in Tolkien’s writings from the 1950s and 60s, variously glossed “wreath, garland, crown” (PE17/59), “twine” (PE17/182), and “twine, wreathe” (PM/347). Thus it seems ᴹ√RIG >> ᴹ√RIƷ >> √RIK >> √RIG, and the sense extended from “crown” to “wreath”.
√RIK¹ ““put forth effort, strive, endeavour, try”
This root was connected to Tolkien’s attempt to translate the phrase “try harder” into Quenya around 1967. √RIK “strive” first appeared in rough notes as a replacement for √NDEB which Tolkien thought was too close to “endeavor” (PE17/167). Tolkien then firmed up the meaning of √RIK in another note, giving it the gloss “put forth effort, strive, endeavour”, so that “try!” = ā rike in Quenya (PE17/93). Another note had √RIK meaning “try” in the sense “endeavour, make an effort, strive (to do something against an obstacle or opponent)”; this note indicated the root was intransitive and the preposition “against” was required before any obstacle (PE17/182). It seems Tolkien did not entirely abandon √NDEB, however, since a similar form √NDAB “endeavor, try, seek opportunity” appeared in Late Notes on Verbs (LVS) from 1969 (PE22/151); see that entry for discussion.
√RIK² “twist; [ᴹ√] jerk, sudden move, flirt”
This root first appeared as unglossed ᴱ√RIQI or ᴱ√RIKI in the Qenya Lexicon of the 1910s with derivatives ᴱQ. riqi- “wrench, twist” and ᴱQ. marikta “wrist” (QL/80). This root also had derivatives in the contemporaneous Gnomish Lexicon such G. raig “awry, twisted, distorted, perverse, wrong, leering (of face)”, G. rig “a snarl, a sneer”, and G. rig- “twist, contort” (GL/64-65). These forms were also linked to G. grinn “ankle (talgrin), wrist (mabrin)” (GL/42) and G. arc “fierce, harsh, ill tempered; awkward, difficult” < ᴱ✶r̄k- (GL/20). The latter reappeared as ᴱN. arch “rough, fierce” >> “rough” in Early Noldorin Word-lists of the 1920s (GL/137), though in the somewhat later Early Noldorin Dictionary, ᴱN. arch “rough” was given a new derivation from ᴱ✶a-rak-wa (PE13/160), and thus was no longer tied to ᴱ√RIKI.
The root ᴹ√RIK reappeared in The Etymologies of the 1930s (EtyAC/RIK(H)) but it was revised to as ᴹ√RIK(H) “jerk, sudden move, flirt” with derivatives like ᴹQ. rinke “flourish, quick stroke” and ᴹQ. rihta-/N. rhitha- “jerk, twitch” (Ety/RIK(H)). In notes from 1959-60 the root appeared again as √RIK “twist” with a single derivative Q. raika “crooked” (VT39/7), a word that in The Etymologies of the 1930s was derived from ᴹ√RAYAK. This 1959-60 appearance seems to be harkening back to its meaning in the 1910s.
√RIL “brilliant (light), brilliance, [ᴹ√] glitter”
This root first appeared as ᴹ√RIL “glitter” in The Etymologies of the 1930s with derivatives like ᴹQ. rilma “glittering light” and ᴹQ. rilya “glittering” (Ety/RIL), along with an extended form ᴹ√MBIRIL “*crystal” (Ety/MBIRIL). Its most notable derivatives was ᴹQ. Silmaril = ᴹQ. silma + ᴹ√RIL, an etymology Tolkien more or less retained thereafter (with ᴹQ. silma >> Q. silima); in the period of the Lost Tales from the 1910s ᴱQ. Silmaril was connected instead to ᴱQ. marilla “pearl” (LT1A/Silmarilli; QL/59). The root √RIL was mentioned several times in Tolkien’s later writtings, mostly in connection to Q. Silmaril, but also Q. Andúril, S. Idril, and S. mithril, and the root was variously glossed “brilliance” (PE17/47), “brilliant” (PE17/112), and “brilliant light” (PM/363).
ᴹ√RIM “abound; large number”
A root in The Etymologies of the 1930s glossed “abound” with derivatives such as ᴹQ. rimbe/N. rhim “crowd, host” (Ety/RIM). A likely precursor to this root appeared in the Qenya Lexicon of the 1910s as ᴱ√‘(A)ṚM(A)R and ᴱ√‘ṚMṚ with a Gnomish form ᴱ√grimri· (QL/32), indicating the actual primitive form was *ᴱ√ƷṚMṚ. Derivatives of this early root include ᴱQ. arm- “gather, collect” and G. grim “host, folk”, the last of these the likely precursor to N. rhim.
The root ᴹ√RIM also appeared in Primitive Quendian Structure: Final Consonants from 1936, glossed “host, large number” >> “number, plenty” (PE21/57). Quenya and Sindarin forms Q. rimbë and S. rim continued to appear in Tolkien’s later writing (Let/382; PE17/50; UT/318), so it is likely the root √RIM remained valid, especially given the prevalence of suffix -rim in Sindarin collective names.
ᴹ√RIN “*circle”
This root first appeared as unglossed ᴱ√RINI in the Qenya Lexicon of the 1910s with derivatives like ᴱQ. rin (rind-) “year, circle” and ᴱQ. rinko “disc, orb, circle” (QL/80). It also had derivatives in the contemporaneous Gnomish Lexicon such as G. rin- “revolve, return, come back; do again” and G. rinc “circular; disc, rondure” (GL/65), but also strengthened forms like G. †drinn “ring, disc” and G. drintha- “to turn (tr.), twist” (GL/30). The root reappeared in The Etymologies of the 1930s with derivatives like ᴹQ. rinda/N. rhenn “circular” and ᴹQ. rinde/N. rhinn “circle” (Ety/RIN).
√RINGI “cold”
Tolkien used very similar forms for Elvish words for “cold” for all of his life. The earliest iteration of this root was unglossed ᴱ√RIŊI in the Qenya Lexicon of the 1910s with derivatives like ᴱQ. rin (ring-) “dew” and ᴱQ. ringa “damp, cold, chilly” (QL/80). The root had similar derivatives in the contemporaneous Gnomish Lexicon such as G. rî “coolness, cool” and G. ring “cool, cold” (GL/65). In The Etymologies of the 1930s Tolkien gave the root {ᴹ√RINGĀ >>} ᴹ√RINGI “cold” with derivatives like ᴹQ. ringe/N. rhing “cold” (Ety/RINGI; EtyAC/RINGI). Primitive forms ✶riñgi “chill” and ✶riñgā appeared in Common Eldarin: Noun Structure from the early 1950s (PE21/80), and Christopher Tolkien mentioned √ring as the basis for cold words in the Silmarillion Appendix (SA/ring).
ᴹ√RIP “rush, fly, fling, hurl”
A root in The Etymologies of the 1930s glossed “rush, fly, fling” with derivatives like ᴹQ. rimpa “rushing, flying” and N. rhib- “to flow like a (?torrent)”, the latter an element in the name N. Rhimdath “Rushdown” (Ety/RIP). This river name appear in early maps from Lord of the Rings drafts from the 1940s (RS/205), but the river was unlabeled in the published version of The Lord of the Rings. As for the root ᴹ√RIP, it reappeared with the gloss “fling, hurl (of something long like an arrow, spear, shaft)” in a rejected list of roots from Quenya Verbal System of the 1940s, having a single derivative in the past form ᴹQ. rimpe “hurled” (PE22/127 note #141). In this list ᴹ√RIP appeared immediately above the root ᴹ√KHAT “hurl”, which also appeared in The Etymologies of the 1930s (Ety/KHAT).
Neo-Eldarin: For purposes of Neo-Eldarin, I think it is better to use the better-known root ᴹ√KHAT for “hurl, fling”, which derivatives like Q. hatal “spear” as late as the 1960s. If ᴹ√RIP is used, it is probably best to give it the meaning of its derivatives from The Etymologies: “rush, fly”.
√RIS “cut, cleave; [ᴹ√] slash, rip”
This root first appeared as ᴹ√RIS “slash, rip” in The Etymologies of the 1930s with the derivative N. risto “rend, rip” (Ety/RIS¹). Tolkien then created a new entry for ᴹ√RIS without deleting the prior entry, with derivatives like ᴹQ. rista/N. rhest “a cut” and ᴹQ. rista-/N. rhista- “cut” (Ety/RIS²); this seems to reflect a conceptual shift of “slash, rip” >> “cut”. Indeed, the root √RIS reappeared in Tolkien’s later writings with the gloss “cut” (PE17/87). Christopher Tolkien gave this root the gloss “cleave” in the Silmarillion Appendix (SA/ris).
ᴹ√RIY “[ᴱ√] scatter”
This root first appeared in the Qenya Lexicon of the 1910s as ᴱ√RIẎI “scatter” (gloss marked with a “?” by Tolkien) with derivatives like ᴱQ. ríma “line of seeds planted, row, series, furrow”, ᴱQ. rísima “scattered, ubiquitous, universal”, and ᴱQ. rista “shoot (sowing), plant, seedling” (QL/80). Tolkien also linked it to the root ᴱ√ORO⁽²⁾, which he said could be analyzed as o- (“over”) + RIẎI; that root had derivatives like ᴱQ. ore (ori-) “seed, grain” and ᴱQ. orya- “sow” (QL/70). In the Declension of Nouns from the early 1930s, Tolkien gave the root form ᴹ√RĪI̯ as the basis for ᴹQ. rí “reed, grass-stem” (PE21/38). There are no signs of this root thereafter.
Neo-Eldarin: In later writings, ᴹ√RED seems to be the basis for “scatter, sow” (PE19/91, Ety/RED), but I think it might be worth retaining the root √RIY as the basis for random scattering as opposed to intentionally scattering for purposes of planting = √RED.