1. A peculiarity of pronunciation, behavior, mode of dress, etc., that distinguishes a particular class or set of persons
2. A slogan; catchword
3. A common saying or belief with little current meaning or truth
One of the two main ways I get etymologies for this blog is the online Oxford English Dictionary (OED). If you've ever tried using it before you know that it is password protected and costs about $300 per year for unrestricted individual access. As much as I love the OED, I'm not paying that. Luckily I can still access it via my alma mater's library website using my student i.d. and password, but recently they have implemented a new login system, delightfully called 'Shibboleth', which I've been wrestling with it for a couple days now. I think I've got it all sorted out, so here's a post in honor of this great Linguistics 101 word.
The etymology of shibboleth is actually not that interesting; It's a Hebrew word meaning "ear of corn" or "stream in flood". The interesting part (and the reason we talked about it in linguistics class) is its usage in the Hebrew Bible as a nearly fool-proof password. An 'open sesame', if you will.
Around 1200BC (give or take 100 years) the people of Gilead beat the tribe of Ephraim in some sort of military battle within the Gilead's territory. After their defeat, the surviving Ephraimites tried to cross the Jordan River to get back to their own territory, but were stopped by Gileadites who were controlling access to the river's fords. Given that all these people were from the same part of the world, they looked more or less the same. This meant that the Gileadites could not reliably identify the Ephraimites on sight alone, so someone came up with an ingenious idea:
Gilead then cut Ephraim off from the fords of the Jordan, and whenever Ephraimite fugitives said, "Let me cross," the men of Gilead would ask, "Are you an Ephraimite?" If he said, "No," then they said, "Very well, say 'Shibboleth'" (שיבולת). If anyone said, "Sibboleth" (סיבולת), because he could not pronounce it, then they would seize him and kill him by the fords of the Jordan. Forty-two thousand Ephraimites fell on this occasion.
Human babies are born with the ability to make a huge array of linguistically distinct sounds, everything from African tribal clicks* to the nearly universal [a]. As we acquire our native language(s), we only practice making the sounds we hear (this is what babbling is for) so the extreme malleability of our vocal tract is replaced by a highly efficient muscle memory. This is why adult foreign language learners find it extremely difficult (if not impossible) to achieve total fluency. French speakers, for example, have a difficult time with English 'th' ([θ] and [ð]) sounds because they don't exist in French. For the same reason English speakers can't pronounce French 'r' sounds very well. So, the Gileadites asking the Ephraimites to say shibboleth is like asking an English speaker to pronounce French rouge** - it's hard, maybe impossible.-Judges 12:5-6
As a side note, while we are forming our language(s)-specific vocal tract, our hearing is becoming highly tuned as well. There is a lot of variability in the way we pronounce different sounds in our language, but not all of the differences are important. For example, the [k] in kit is technically different than the [k] in skill. In kit it is aspirated (which means you release a puff of air when pronouncing it, IPA: [kʰ]), but in skill it is not (IPA: [k]). If you don't believe me, hold a lit match in front of your mouth and say each word, the flame will dance for kit but won't for skill. The difference in aspiration is not important in English so we don't notice it, but in some other languages it is. Asians famously cannot distinguish [l] and [ɹ]*** very well and Westerners have a difficult time hearing Chinese tones for similar reasons.
*Zulu uxolo: "Excuse me!"
** I couldn't get the link to work correctly, but to hear the French pronunciation, copy and paste this link: http://french.about.com/library/media/wavs/rouge.wav
***The English 'r' is represented by [ɹ] in the International Phonetic Alphabet (IPA).
****Okay, I stand corrected: the etymology is kind of cool, thanks Balashon