And the Gileadites seized the passages of the Jordan before the Ephraimites; and it was so, that when those Ephraimites who had escaped said, ``Let me go over,'' that the men of Gilead said unto him, ``Art thou an Ephraimite?'' If he said, ``Nay,'' then said they unto him, ``Say now 'Shibboleth.''' And he said ``Sibboleth,'' for he could not frame to pronounce it right. Then they took him and slew him at the passages of the Jordan; and there fell at that time of the Ephraimites forty and two thousand. (Judges 12:5--6)The work is now available as an interactive program on the web: Shibboleths. (Without recording. This is the fourth implementation of the work: C++, Flash, javascript+XML, processing.)
Here are a number of screen captures from the original computer installation.
Read the paper "Shibboleth: Exploring cultural boundaries in speech" that appears in the conference proceedings.