The communication skills, oral-motor function and respiration patterns of 20 girls with Rett syndrome were studied. Loss of communication has been previously recognized as a sign of the onset of Rett syndrome, but oral-motor dysfunction has not been reported. All the girls showed a regression in speech and language function by the onset of stage II Rett syndrome. Changes in oral-motor function and respiration correlated with the progression of the disease from stages II to IV.