whisper (v.) Look up whisper at Dictionary.com
Old English hwisprian "speak very softly" (only in a Northumbrian gloss for Latin murmurare), from Proto-Germanic *khwis- (cf. Middle Dutch wispelen, Old High German hwispalon, German wispeln, wispern, Old Norse hviskra "to whisper"), imitative and probably related to Old English hwistlian "to whistle." Related: Whispered; whispering. The noun is from 1590s.