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!

Gnomish

thlid-

verb. to sort out, sift, sieve, discriminate

A verb appearing as G. thlid- “to sort out, sift, sieve, discriminate” in the Gnomish Lexicon of the 1910s derived the early root ᴱ√SḶTḶ (GL/73; QL/84).

Neo-Sindarin: I would adapt this Gnomish verb as ᴺS. lhid- “to sort out, sift, sieve, discriminate” based on a neo-root ᴺ√SILIT, since in Tolkien later Sindarin phonology, initial sl became lh rather than thl.