Proper Quenya form of the name of the Sea Elves in Silmarillion drafts from the 1930s: ᴹT. Soloneldi, though only the Telerin form appeared in the tales (LR/214). The Quenya form appeared only in The Etymologies, where it was given as compound of solor “surf” and nyello “singer” (Ety/NYEL, SOL).
Quenya
Solonel
solonel
Solonel (Soloneld-) noun, a name of the Teleri (here in the sg, pl. Soloneldi). Note that this form is influenced by Telerin; pure Quenya has Solonyeldi, sg. #Solonyel. (PHAL/PHÁLAS, NYEL, SOL)