A shibboleth is a way of speaking that identifies one as a member of a group. The purpose of a shibboleth is exclusionary as much as
In Judges 12:4, two Semitic tribes, the Ephraimites and the Gileadites,
have a battle. The Gileadites defeat the Ephraimites, and set up a
blockade to catch the fleeing Ephraimites. The sentries asked each
person to say the word shibboleth. The Ephraimites, who had no sh sound
in their language, pronounced the word with an s and were thereby
unmasked as the enemy and slaughtered.