Shibboleth (shib'e lith)

In the 12th chapter of Judges, Jephthah and his men were victorious over the warriors of Ephraim. After the battle, Jephthah gave his guards the password "shibboleth" to distinguish friends from foes; he picked the word because the Epharaimites could not pronounce "sh" sound. The strategy was shrewd and many of his enemies were captured and killed. Thus, the term has come to mean a peculiarity of pronunciation, usage or behavior that distinguishes a particular class or set of persons. It can also mean slogan; a catchword.