Shibboleth

shibboleth [SHIB-uh-lith]
n. a peculiarity of pronunciation, behavior, mode of dress, etc., that distinguishes a particular class or set of persons; a custom or practice that betrays one as an outsider

[Hebrew "a torrent of water"]

I'm not sure how old I was the first time I came across the word shibboleth. However, I distinctly remember as a young child learning the shibboleth concept, with regard to Japanese soldiers in World War II. As the story went, it was difficult, yet important for American GIs to distinguish between a Japanese and a Chinese -- the former being our enemy, the latter our friend. Because it was hard for the Japanese tongue to pronounce the L in words like Leghorn and lollipop, but supposedly no problem for the Chinese, American soldiers, having captured an Oriental of unknown nationality, would require the captive to say one of those L words. If Leghorn came out Reghorn, the person was Japanese. Even though I now suspect this legend of my youth was apocryphal ("of questionable authenticity"), it was a good myth to introduce the shibboleth idea.

David Plotz, a writer and editor for Slate.com and author of Good Book: The Bizarre, Hilarious, Disturbing, Marvelous, and Inspiring Things I Learned When I Read Every Single Word of the Bible, recently discussed the word shibboleth in a Slate article:

When I was reading Judges one day, I came to a complicated digression about a civil war between two groups of Israelites, the Gileadites and the Ephraimites. According to the story, the Gileadites hold the Jordan River, and whenever anyone comes to cross, the guards ask them to say the password, shibboleth. The Ephraimites, for some unexplained reason, can't pronounce the sh in shibboleth and say "sibboleth" instead. When an Ephraimite fails the speech exam, the Gileadites "would seize him and slay him." I've read the word shibboleth a hundred times, written it a few, and probably even said it myself, but I had never understood it until then.

In contemporary usage, a shibboleth is not limited to how a word is pronounced or mispronounced. A secret handshake can be a shibboleth, distinguishing those in the group from those outside. Also, a collection of jargon terms largely unknown to outsiders can serve as a shibboleth to distinguish insiders. A person, for example, who speaks about Pecota, Win Shares and Ultimate Zone Rating is one of a subset of baseball fans in the sabermetric community. (Sabermetric derives from the acronym SABR -- Society for American Baseball Reasearch + metric. A sabermetrician is one who uses advanced mathematical measures of baseball statistics to understand the value of various contributions to the game.) If someone mentions to me Derek Jeter's UZR, I know immediately from that shibboleth that he is a sabermetrician and not just a casual or old-school baseball fan.