"What's the hubbub, Bub?" said Bugs Bunny. But, buddy, what is a hubbub? Is it the murmuring rhubarb and babble of a rubbernecking rabble, or the bawdy hubba-hubba of bad boys eyeballing a bobbysoxer, or the blubbering and bawling some lub who's been robbed? Is it simply general hullaballoo? Or is it something more threatening? A band of barbarians? A howling, perhaps as of a haboob?
If you look in the Visual Thesaurus, you see one node: "loud confused noise from many sources"; synonyms are brouhaha, uproar, and katzenjammer. But the Oxford English Dictionary, with its historical perspective, gives a small set of definitions, at the softer end of which is the rumbling murmur I remember from the mobs in the Banff Hot Springs, where I often bathed as a child, but at the louder end of which is a general hue and cry, even the shouting of a war cry. Spenser, in The Faerie Queene, used it thus: "They heard a noyse of many bagpipes shrill, And shrieking Hububs them approching nere." Shrieking hubbubs! They sound almost like banshees.
Well, hubbub does appear to have something in common with banshee: an Irish origin. It is, by old accounts, an Irish outcry, cognate perhaps with the Scots Gaelic interjection of aversion or contempt, ub! ub! ubub! This is not to say we know its source ab ovo, but earliest citations lead me to think this purported source is no booboo.
But does hubbub sound threatening enough? There's a reason it has shifted to a more general crowd sound, and I'm inclined to think it has to do with its greater resemblance to muddled incoherent speech sounds. After all, our wordbarbarian comes from the Greeks' impression of the speech sounds of foreign rabble: barbarbarbar.
Still, for the Celts, ubub was not simple urban rumble, nor even some exuberance. Indeed, the war cry of the ancient Irish was abu! (Compare this to the war cry of the juvenile Anglophone, leaping out from behind a piece of furniture: Boo!)
It's not the noise of a thousand tongues, though, not if they're all saying hubbub, because this is one of those few words one can say entirely without the use of the tongue. Orthographically it's at least as odd: almost a palindrome, except the h is an incomplete or burst b; its repeating sequences look a bit like one of those 3-D smudgeeos that used to feature in newspaper funny pages. Rotate it 180˚ and you get something spelling about as opposite a sound sequence as you could want: qnqqny.
But it hasn't always been spelled exactly that way, as the Spenser quote hints. Other forms the OED lists through its history are hooboube, hooboobe, hoeboube, whobub, hubub, hobub, whoo-bub, whoopubb, hoobub, howbub, how-bub, and hub hub. Put them together and they make a regular whoop-up, more like a frat-boy noise than some hot pool conversation. And you thought word tasting was a subdued hobby!