Some years ago, there was a series of stories in a magazine about dates that did not go well. In one of the stories, a woman met her date at a Mexican restaurant. When they ordered dinner, her companion asked for tortillas, but he pronounced the word "dor-dee-yas." Although he did not know it, the hapless gentleman's pronunciation proved to be a shibboleth that meant there would be no second date.

The term shibboleth comes to us from a rather brutal story in the Old Testament, which appears in Judges 12:4-6. One tribe of the Israelites (the Gileadites) fought and defeated another tribe (the Ephraimites). After the battle, survivors were crossing the River Jordan, and Gileadites who were guarding the river challenged would-be crossers to say the Hebrew word shibboleth. In the dialect of the Ephraimites, the word is pronounced with an initial "s", not "sh," so the Gileadites slew anyone who said "sibboleth."

Unfortunately, this isn't the only time that linguistics has been put to deadly purpose. Stories about people being killed over pronunciation come from the Dominican Republic (the so-called  "Parsley Massacre"), and from conflicts between the Dutch and Germans and between the Sinhalese and Tamils. It's said that during World War II, American troops in the Pacific used the word lollapalooza as a shibboleth to test approaching soldiers, on the theory that Japanese infiltrators would not be able to pronounce the word correctly.

A story of a less violent nature that I used to hear during the Vietnam era concerned American draft dodgers who had fled to Canada. Supposedly these Americans would try to sneak into the U.S. for visits, masquerading as Canadians. At the American border, they'd be challenged to say the alphabet as fast as they could. If they ended with "zee" for Z, it would unmask them as Americans, since Canadians say the letter Z as "zed." This story has an apocryphal feel to it (although others have heard it as well), but true or not, it's a good example of a shibboleth.

A shibboleth does not always have to be about pronunciation. My father-in-law grew up in Glasgow, and he told us that in his younger days, people would be stopped and challenged to say a prayer. The Lord's Prayer marked Protestants, and a Hail Mary marked Catholics. Saying the wrong prayer to the wrong people could result in a beating.

In spite of the violent origins of the term, a shibboleth these days can also simply refer to a word or phrase that identifies membership (or lack of membership) in a group. My personal experiences of shibboleths all have to do with this considerably less frightening sense.

For example, people learn the language quirks that are unique to their region. I've lived in Seattle for a long time, hence I've mastered the many shibboleths that mark a true Pacific Northwesterner. I can correctly pronounce local names like Puyallup ("pew-AL-up"), Sequim ("squim"), and Alki ("AL-kai"). I know that Wapato is "WOP-ah-toe," and that the name of our city of Des Moines is pronounced with the "s" at the end of "Moines." I know that our famous local market is not "Pike's Market" but "the Pike Place Market," and I would never say "Mount Rainier is visible today"; Seattleites say "The mountain is out." At Seattle-area high schools, the event known everywhere else in the United States as a Sadie Hawkins dance is known as Tolo. A person who hasn't mastered these shibboleths is clearly an outsider.

No matter where you live, you probably can reel off a similar list of local names and terms that confound outsiders. In the United States there are many place names and terms derived from Native American languages, whose contemporary pronunciation can be learned only by experience, like the ones I listed from the Northwest. But Native American words are only one source, albeit a rich one, of shibboleths. A friend of mine who moved to California said it took him a long time to understand that the city of La Jolla—whose name comes from Spanish—is pronounced "Lah HOY-ah."

The British certainly have many shibboleths. One is the name St. John; if it's part of a personal name, St. John is pronounced "SIN-jin." Here's a video snippet of James Bond instructing a valet in the correct way to pronounce his alias of "St John Smith":

Shibboleths have come up in my professional life as well. During my years at Microsoft, I learned Microspeak, as it's called—the jargon of Microsoft insiders. In my era, insiders used lingo such as blue badge (a full-time employee), to S+ (to schedule a meeting), OOF (the mis-initialed out of office), bug bash, and pri 0 (for priority zero, meaning a highest-priority item). (I wrote about some of these terms in an earlier piece.)

When I moved to Amazon, not only did I have to learn a new insider jargon (dogs not barking, undifferentiated heavy lifting), but I discovered the real power of shibboleths: Microspeak was not welcome. The group I was in at Amazon was at pains to distinguish itself from all things Microsoft, and those of us who'd moved over from Microsoft were taken aside and advised that using a term like pri 0 in front of certain executives was a definite no-no. I've since moved to Tableau, where we have our own shibboleths: we don't say verbiage, we say wordage, and our insider term for a bug bash is WAM (for "whack-a-mole").

Not long ago I ran across another unexpected use of the term shibboleth. We were working with a feature that allows you to sign in to your organization's site—to a corporate web site or a university site—and from there, get access to external sites like the payroll site or an inter-library site. One prominent product that permits this sort of "single sign-on," as it's called, is named Shibboleth. This struck me as a perfect name for software that helps determine whether you are who you say you are.

It's frightening to think about a situation in which what you say or how you say it could have a serious effect on your health. I imagine that most of us have failed a shibboleth test at one time or another in our lives. Fortunately, the worst effect has probably simply been to be labeled as an outsider.