A verb appearing as ᴱQ. tyasa- “test, try, pick, choose” in the Qenya Lexicon of the 1910s under the early root ᴱ√TYASA of similar meaning (QL/49).

Neo-Quenya: I think it is worth retaining ᴺQ. tyas- for purposes of Neo-Quenya based on a Neo-Root ᴺ√TYATH, so archaically pronounced tyaþ- (still reflected in tengwar spelling). I think tyas- means “test or try” something out to see if you like it, hence also “pick or choose” among options to see if something is good.