Origin of sough19th circa from Northern dialect, dialectal from Middle English swough from Old English swogan, to sound from uncertain or unknown; perhaps Indo-European base an unverified form (s)wa?h-: see echo
Origin of soughME swowen, soghen < OE swogan, to sound
intransitive verbsoughed, sough·ing, soughs
Origin of soughMiddle English swowen, soughen from Old English swōgan
(third-person singular simple present soughs, present participle soughing, simple past and past participle soughed)
Old English swÅgan, from Proto-Germanic *swÅganÄ….