A hypothetical early root serving as the basis for Gnomish words having to do with “otherness”, such as G. eleg “other”, G. elfel “different, like something else” and possibly also eltha- “to alter, change”, though the last word seems to have been part of a separate etymological paradigm (GL/32). This collection of words also included G. elm “wonder” and elma- “marvel at, admire”. Similar forms appeared in the 1920s: ᴱN. elvennai “wonderful, marvelous” and ᴱN. elven “wonder, wonderment”, the latter with a Qenya cognate ᴱQ. elmenda (PE13/143, 161).
Some of this sense of wonderment may have resurfaced in the root √EL in the Quendi and Eldar essay of 1959-60, where Tolkien said of ELE that “according to Elvish legend this was a primitive exclamation, ‘lo! behold!’ made by the Elves when they first saw the stars” (WJ/360). On this basis, I think it worth concocting an extended Neo-Eldarin root ᴺ√ELEM “wonder, marvel” to salvage the “wonder” words from the 1920s. It might also be worthwhile to concoct an extended root ᴺ√ELEK “different, strange; other” to salvage Gnomish “other” words from the 1910s, but that one is more of a stretch and I no longer recommend its use. Neologisms based on later roots serve better for that purpose.
A root in the Qenya Lexicon of the 1910s glossed “drive, push, thrust, send forth”, with derivatives like “spear” and “thrust” (QL/35). It was also the basis for the rootᴱ√LEHE “come, be sent, approach” (QL/52). There are indications in the contemporaneous Gnomish Lexicon that Tolkien gradually gave up this root: he first gave the forms G. elta- “to thrust, dig, poke (inward)” and G. elt “a dig, a poke (probe)”, then apparently revised them to G. elta-/eltha- “draw, tug, lug” and G. elt “a tug, lug”, representing a semantic shift from “push” to “pull” (GL/32).
These Gnomish forms were all eventually deleted and replaced by G. eltha- “to alter, change” and G. elt “a change”. These replacements are sufficiently distinct in meaning that I think they represent the introduction of a new root ✱ᴱ√ELE connected to “wonder” and “otherness”; see that entry for details. Meanwhile, it seems the Gnomish “thrust” words were transferred to the root ᴱ√ḶTḶ, as in G. ilta- “to stick in, prod, prick” (GL/51).