Old English næctigalæ, nihtegale, compound formed in Proto-Germanic (cognates: Dutch nachtegaal, German Nachtigall) from *nakht- "night" (see night) + *galon "to sing," related to Old English giellan "to yell" (from PIE root *ghel- (1) "to call"). With parasitic -n- that appeared mid-13c. Dutch nightingale "frog" is attested from 1769. In Japanese, "nightingale floor" is said to be the term for boards that creak when you walk on them.
French rossignol (Old French lousseignol) is, with Spanish ruiseñor, Portuguese rouxinol, Italian rosignuolo, from Vulgar Latin *rosciniola, a dissimilation of Latin lusciniola "nightingale," diminutive of luscinia "nightingale," which, according to de Vaan, "might be explained with haplology from *lusci-cania 'singing in the night' or 'blind singer', but this is speculative."