(pl. felethrin)
Sindarin
falathren
noun/adjective. of the shore
falathren
noun/adjective. Shore-language (one of the names for Common Speech)
falathren
proper name. Shore-language
Elements
Word Gloss falas “beach, shore, strand, surf(line)” -ren “adjective suffix”
falathren
of the shore
falas
shore, foaming shore
(pl. felais) (beach, coast, strand, line of surf; the word was especially used of the western seaboard of Beleriand) (VT42:15). Adj.
faur
shore
(beach), pl. foer, coll. pl. forath (VT46:15)
habad
shore
(i chabad, o chabad), pl. hebaid (i chebaid). Archaic pl. hebeid (LR:386).
rhast
shore
(?i thrast or ?i rast – the lenition product of rh is uncertain), pl. rhaist (?idh raist).
In the drafts of the Lord of the Rings appendices, a Late Noldorin [Sindarin] name for the common tongue spoken along the shores of western Middle-earth that would eventually develop into Westron (PM/32). This name is most likely a combination of falas “shore” and the adjective suffix -ren, after undergoing the phonetic change: [[s|medial [s] became [θ] before [l], [r]]].
Conceptual Development: The word N. Falathren also appeared in The Etymologies from the 1930s, but there it was an adjective referring to the region or Elvish folk of the Falas (Ety/PHAL). Their dialect of Ilkorin was called Falathrin (LR/170), of which a few examples appeared: Fal. Ariad(or) (Ety/AR²) and Fal. galbreth (Ety/BERÉTH).