susurrationn.

susurration (n.)"a whispering, a murmur," c. 1400, from Latin susurrationem (nominative susurratio), from past participle stem of susurrare "to hum, murmur," from susurrus "a murmur, whisper," a reduplication of the PIE imitative base *swer- (2) "to buzz, whisper" (cognates: Sanskrit svarati "sounds, resounds," Greek syrinx "flute," Latin surdus "dull, mute," Old Church Slavonic svirati "to whistle," Lithuanian surmo "pipe, shawm," German schwirren "to buzz," Old English swearm "a swarm").