Unless you've been living under an Internet-free rock, you've probably seen the enthralling video of Scotland's Susan Boyle singing on the television show Britain's Got Talent. According to the latest numbers, the video of Boyle's performance has already attracted more than 100 million online views. But it's not only her singing prowess that is attracting worldwide attention: it has also been reported that "Web searches for the term gobsmacked spiked after Boyle used the British slang meaning utterly astonished when describing her reaction to newfound widespread acclaim."

The graph for gobsmacked on Google Trends bears out the huge spike in online searches, buoyed by Boyle's use of the term in numerous interviews. She told CNN, for instance, "I'm gobsmacked, absolutely gobsmacked." Previously, this colloquialism hadn't circulated much outside of the British Isles, but now it's fair to say that Boyle has brought it to much wider notice in the United States and elsewhere.

Even if non-Brits have encountered gobsmacked before (defined by the Visual Thesaurus as "utterly astounded"), they might not know its derivation. Gob is UK slang for "mouth," as in Willy Wonka's Everlasting Gobstoppers, pieces of hard candy that "stop" (close) your "gob" (mouth). (Americans would call them jawbreakers.) So gobsmacked equates the feeling of astonishment with the feeling of being smacked in the mouth.

British usage of gobsmacked has only become prominent since the 1980s, but the earliest known appearance of the term actually goes back to 1956. As Jerry Friedman noted recently on the Usenet newsgroup alt.usage.english, Google Book Search now reveals this passage from the novel Woman of Bangkok: "I'm so amazed that only the Malderbury dialect can express my condition: I'm 'properly gob-smacked.'" The author of Woman of Bangkok is one Jack Reynolds, but this is likely a pseudonym: also in 1956, the book was published in Britain as A Sort of Beauty under the name Jack Jones. And just to add to the mystery, the "Malderbury dialect" to which the narrator refers is a fabrication: there's no such place as Malderbury.

We can guess that Jack Reynolds/Jones had some ties to northern England or Scotland, where the term gob has long been a slang term for "mouth." According to Michael Quinion of World Wide Words, the word likely spread from Scottish Gaelic (where gob can mean "beak" and also suggests gab "talk"), primarily via insulting phrases like "Shut your gob!" ("Be quiet!"). So it's fitting that a Scot like Susan Boyle, who hails from the town of Blackburn about twenty miles from Edinburgh, should be the one to bring gobsmacked to international recognition.

And that wasn't the only colorful slang that Boyle used in her post-performance interviews. She also told ITV, the network that broadcasts Britain's Got Talent, "I was poleaxed with joy when I came off [the stage]." A poleaxe is an axe for slaughtering cattle (or a medieval battle-axe), which has spawned a verb meaning "fell with or as if with a poleaxe." The Oxford English Dictionary dates the participial adjective poleaxed back to 1851 (the English poet Martin F. Tupper wrote, "And down like a pole-axed bull he drops, And weak on the threshold lies"). Like gobsmacked, the figurative sense of poleaxed to mean "astounded" seems to have been popularized in the 1980s, but it wasn't restricted to British usage: American author Judith Krantz described a male character in a 1983 novel as staring at a woman with a look of "poleaxed yearning."

Other Boyleisms are more strictly regional. In another ITV interview, she mused about what it would be like if she advanced in the competition far enough to join in the Royal Variety Show, performing for Queen Elizabeth II: "She is a very regal lady, very nice, so I would be nice too, and just get up there and give it a bit of wellie." Wellie (or welly) is British slang for "power, vigor, effort." It's short for Wellington boot, with the idea being that applying effort is like putting one's foot on an accelerator, or possibly giving something a hard kick.

Boyle further recalled, "Being on that stage and being on the other end of that reception was absolutely fantastic. It went down a bomb." Americans typically use bomb to mean "an event that fails badly or is totally ineffectual," but Brits use it in precisely the opposite way to mean "a success." (Of course, younger Americans now approximate British usage by saying "That's the bomb!" to express a positive sentiment.) The peculiar phrasing went down a bomb is a way of saying something (particularly a performance) succeeded smashingly. This also seems to be common to Scotland and northern England. The OED provides a 1963 quotation from Liverpool's own John Lennon about a pre-Beatles band: "Once, Paul McCartney and I played Reading as the Nurk Twins. Went down a bomb, I recall."

If you want to learn more about regional dialects of British English like Boyle's, take a break from the incessant YouTube videos to check out these great online resources: