This paper describes and compares the mandibular speech envelope and interocclusal dimensions, at the closest speaking and postural positions, for a group of 30 dentate subjects measured at separate data-collecting sessions. Mandibular movement was recorded by electrognathograph during recitation of a general phonetic articulation test containing all speech sounds. Comparison of the speech envelope and interocclusal dimensions between each recording session revealed no significant differences among them. An overall mean value calculated for the closest speaking space and postural interocclusal space from all recordings was significantly different (P > .05), with the closest speaking space the larger; however, considerable individual variation was noted.