The unglossed root ᴱ√QINI appeared in the Qenya Lexicon of the 1910s with derivatives like ᴱQ. qíne “squeaking” and ᴱQ. qíni- “speak high, squeak” (QL/77).
Neo-Eldarin: I think it worth positing a Neo-Eldarin root ᴺ√KWIN “squeak” to preserve these Early Qenya words, though it conflicts with √KWIN “crest, salient or top edge”.
A root Tolkien introduced to explain S. pinnath “ridges” (class plural of pind) in Pinnath Gelin “Green Ridges” (PE17/173). It appeared below √PED “fall in steep slant, incline, slope”, which was the basis for the similarly formed S. pend “slope”. In notes elsewhere Tolkien said that pinnath was a blending of the two plural forms of pend: general plural pind and class plural pennath (PE17/24), but it seem he later decided pind was from the distinct root √KWIN.