[ᴱ]*√KAWAK root. “*caw, croak”
This (hypothetical) onomatopoeic root served as the basis for primitive forms ✶k(a)wāk “crow” from the Quendi and Eldar essay of 1959-60 (WJ/395) and ✶kāwāk “frog” in notes from the late 1960s (VT47/36). These same late 1960s notes also mention onomatopoeic kā “crow” as a homophone of kā “house” (elsewhere derived from √KAW). Thus the root probably meant something like “caw, croak”.
The root √KAWAK is probably a later iteration of the root ᴱ√QAHA or ᴱ√QAQA from the Qenya Lexicon of the 1910s, unglossed but with derivatives likes ᴱQ. qá “duck” and ᴱQ. qaqa- “quack, squawk, cackle” (QL/76). This root is probably also the basis for ᴱQ. qaine “wailing” from the phrase ᴱQ. ve maiwin qaine “like gulls wailing” in the ᴱQ. Oilima Markirya poem written around 1930 (MC/213), and so perhaps actually meaning something more like “squawking”.
Neo-Eldarin: For purposes of Neo-Eldarin, I think the 1910s derivatives of ᴱ√QA(QA) could be salvaged as derivatives of √KAWAK > *k(a)wa(k), but I think the 1959-60 Q. quáco “crow” is too close in form to late 1960s quácë “frog”, so I recommend using 1930s ᴹQ. korko for “crow” instead. I suspect √K(A)WAK is a Quenya-only root, since phonetic changes (kwa- > pa-) would have ruined the onomatopoeic nature of the root in Sindarin.