The root √SIR and similar roots meant “flow” for most of Tolkien’s life. The earliest form of this root was ᴱ√SIŘI [SIÐI] “flow” in the Qenya Lexicon of the 1910s with variant sini and derived forms like ᴱQ. sindi “river” and ᴱQ. síre “stream” (QL/84). The latter word became “river” in Tolkien’s later writings, and words appearing in the contemporaneous Gnomish Lexicon like G. sîr “river” and G. siriol “flowing” (GL/67-68) rather than ✱✱sidh- indicate Tolkien very early revised the root to ✱ᴱ√SIRI. Indeed, the root was ᴹ√SIR “flow” in The Etymologies of the 1930s, and the root appeared with this form and essential meaning several times in Tolkien’s later writings (PE22/127, 135).
Primitive elvish
ran
root. wander, stray, meander, go on an uncertain course, go aside from a course (commanded or self-chosen); err
rānā
noun. moon
ranthlā
noun. ladder
rantā
noun. tracks and trails of travellers or explorers that had become habitual and could be followed by others
sir
root. flow
teg
root. line
Tolkien used a number of similar roots as the basis for “line” words throughout his life. The earliest of these appeared in the Qenya Lexicon as ᴱ√TEHE [teχe] “pull” (gloss marked with a “?” by Tolkien) with derivatives like ᴱQ. tea “straight”, ᴱQ. telya “attractive; importunate”, and ᴱQ. tie “line, direction, route, road” (QL/90), the last of these surviving more or less unchanged all the way into the published version of The Lord of the Rings (LotR/377). The early root ᴱ√TEHE also had derivatives in the contemporaneous Gnomish Lexicon such as G. tê “mark, line; track; path”, G. tî or tion “straight”, and G. tîr “honest; esteem, regard, honour”, originally “straight, upright” (GL/69, 71). Primitive ᴱ✶tegna > ᴱQ. tína/ᴱN. tain “straight” from Early Noldorin Word-lists from the 1920s may represent a shift in the form of the root to ✱ᴱ√TEGE (PE13/153, 165).
In The Etymologies of the 1930s the root appeared as {ᴹ√TEƷ >>} ᴹ√TEÑ “line, direction” with derivatives like ᴹQ. tie/N. tê “line, way” and ᴹQ. téra/N. tîr “straight, right” (Ety/TEƷ, TEÑ). In the Outline of Phonology Tolkien gave √TEG “line”, whereas √TEÑ was given as the basis for Q. tenna “a thought, notion, idea” and thus clearly with a different meaning; see the entry √TEÑ for further discussion. In any case it is clear that Tolkien considered various ancient velar consonants for the second consonant of this root, all ultimately vanishing in the child languages with similar vocalic effects: 1910s teχ-, 1920s teg-, 1930s {teʒ- >>} teñ- and 1950s teg-.
Neo-Quenya: For purposes of Neo-Eldarin, I would assume this root was √TEƷ in order to preserve the validity of the word téma “series”. This is because Tolkien kept vacillating on the development of gm, but usually had gm > ngw, so that teg-mā > tengwa, not téma.
ler
root. free
A root appearing twice in a list of roots from 1959-60, the first time described as “free (of moveable things or moving things), able to move as willed, unimpeded, unhampered, loose, not fixed fast or static” and the second time as “am free to do, sc., am under no restraint (physical or other)” (VT41/5-6). In the second instance it was compared to √POL which had the sense of being physically able to do something. It seems that √LER = “able to do something because there is nothing preventing it” vs. √POL = “able to something because of physical ability”. It might also be contrasted with √LEK which has the sense of freeing something that was once bound, whereas with √LER the thing that is free may have never been bound in the first place.
sīru
noun. stream
This root first appeared as ᴹ√RAN “wander, stray” in The Etymologies of the 1930s with derivatives like ᴹQ. ranya-/N. rhenia- “to stray”, ᴹQ. ránen/N. rhaun “errant”, and ᴹQ. Rana/N. Rhân as names for the Moon (Ety/RAN). These Moon-names also appeared in earlier writings but without clear etymologies (LT1/192; GL/64). Such Moon names continued to appear in later writings, for example: Q. Rána “Wayward” (S/99). The root √RAN itself was mentioned quite frequently in Tolkien’s later writings with glosses like “wander, stray” (PE17/182), “wander, stray, go on uncertain course” (VT42/12) and “err, go aside from a course (commanded or self-chosen)” (PE17/78).