they said, "All right, say 'Shibboleth.' " If he said, "Sibboleth," because he could not pronounce the word correctly, they seized him and killed him at the fords of the Jordan. Forty-two thousand Ephraimites were killed at that time.

It was the password ... it either allowed entry or it brought about immediate death. Looks like the Ephraimites had a hard time pronouncing it!