This paper presents quantitative information concerning the shifts in pitch that occur when a talker changes the power level of his voice from “normal” to “loud” or from “normal” to “soft” under natural speaking conditions; in addition, data are given of the shift in frequency of the first formant (F1) for an increase in speech power level. The shifts were measured for the following sets of words: (1) a group of recordings of the same word, each spoken by a different talker, and (2) a group of different words spoken by the same talker. For each word, the shifts accompanying the change in speech power level were computed for five points along the pitch and formant tracks—from the beginning to the end of the word. For a change in speech power level from “normal” to “loud,” the average change in pitch for all of the data was approximately 40%, and the change in F1 was approximately 12%. For a change in speech power level from “normal” to “soft,” the over-all average decrease in pitch was approximately 12%.