This MATLAB exercise analyzes an audio file which contains a period of background signal, followed by a period of spoken speech, and ending with a period of background signal. The analysis is conducted on a frame-by-frame basis, and, based on a set of short-time log energy and short-time zero crossings rate parameters, the program determines the frame that is the best estimate of the beginning of the speech signal, and the frame that is the best estimate of the end of the speech signal. The file '4.1 Speech Endpoint Detector.pdf' provides a User's Guide for this exercise.