A noun in the Gnomish Lexicon of the 1910s glossed “foot (of things), base, pedestal, pediment” (GL/68), based on the early root ᴱ√TALA “support” as suggested by Christopher Tolkien (LT2A/Talceleb).
Sindarin
taltha-
verb. to slip, slide down, collapse
A neologism posted by Steve - Ríon on 2018-11-25 in the Vinyë Lambengolmor Discord Server (VLDS) with the gloss “to slip”. It is based on OS. taltha-, attested in its future form talthathō- and derived from ✶talta- [talat-] “slip, slide down, collapse” (PE22/133).