spal(as)

root. *foam

The root ᴹ√SPAL with extended form ᴹ√SPÁLAS appeared in The Etymologies of the 1930s as a variant of ᴹ√PHAL(AS) (Ety/SPAL). Given that both ᴹ√SPAL(AS) and ᴹ√PHAL(AS) produce the same results in both Quenya and Noldorin, it is had to say which derivatives belong to which root, but Ilk. espalass and ᴹT. spalasta- are definitely from ᴹ√SPAL(AS) (Ety/PHAL; EtyAC/PHAL). This root is likely a later iteration of unglossed ᴱ√Palas or ᴱ√Palat from the Qenya Lexicon of the 1910s, where Tolkien indicated it was related to ᴱ√PḶTYḶ “✱strike; flat of the hand” (QL/72); it had derivatives like ᴱQ. palasse “foam, splashing” and ᴱQ. palasya- “splash, foam” (QL/72), and it might be related to G. osp(a) “foam” from the contemporaneous Gnomish Lexicon (GL/63).

In general, however, Tolkien used √PHAL (earlier ᴱ√FALA) much more regularly as the basis for wave/beach/foam words.