A lesson in the use of pronunciation keys provided in English dictionaries, which is designed for adult foreign students, includes notes to the teacher concerning preliminary activities, discussion of the approach, a description of the lesson sequence, and a lesson designed for the student's use. The three-segment lesson, designed for second- and third-level students of English as a second language, aims to simplify and demystify the pronunciation key using two salient elements: diacritical marking and respelling. After prefatory remarks, the students' lesson outlines the letters of the alphabet in combination with diacritical marks and, for each item, gives an example of the sound in a simple familiar word, a respelling or transcription, and notes when applicable. A final section briefly discusses the schwa. (MSE)