An objective measure of the quality of speech communications channels was developed and described by Steeneken and Houtgast [J. Acoust. Soc. Am.67, 318–326 (1980)]. By calculating the speech transmission index (STI), this method provides an estimate of speech intelligibility for a variety of communication distortions, but the method has been validated only for the Dutch language. For this reason, questions arise about its applicability for use with English. Using the standard Harvard PB‐word test for speech intelligibility, it was shown that the STI method is a valid method for testing the speech transmission of communications channels intended for use with the English language. New STI curves were generated for both the English PB‐word test and the Modified Rhyme Test.