Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
rod
noun. tube, stem
rodothlim
collective name. Rodothlim
rodos
noun. cavern
rodrin
noun. cylindrical
grûd
noun. cavern
grûda
noun. cave
gwiniel
noun. lady
rogli
noun. little pipe (especially musical)
sinc
noun. metal
A noun from the Gnomish Lexicon of the 1910s appearing as G. sinc “metal” (GL/67), clearly the cognate of ᴱQ. sink “mineral, gem, metal” from the root ᴱ√SINI (QL/83).
Neo-Sindarin: I would retain this word for purposes of Neo-Sindarin, but would revise its sense to ᴺS. sinc “mineral”, derived from the primitive form ✶sinki (PE17/108) which may itself mean “✱mineral”; see that entry for discussion. I would use N. tinc for “metal”.
teld
noun. roof
telthon
noun. roof
A noun for “cavern” in the Gnomish Lexicon of the 1910s based on the early root ᴱ√roto (GL/65). In early editions of the Gnomish Lexicon as published, the form was incorrectly given as rodrin, but errata confirmed that word actually meant “cylindrical” and the word for “cavern” was properly rodos (PEE for issue 11), as reported by Christopher Tolkien (LTA2/Rothwarin).