Patients were tested before and after undergoing surgical premaxillary osteotomy for correction of skeletal and soft-tissue discrepancies. Both structural and speech measurements were made before surgery and for a year after surgery. The role of hearing and oral sensation in adaptation to surgery was evaluated. Immediately after surgery, speech was disrupted. Distortions of |s| predominated. However, there were no long-term effects on speech. Hearing and oral sensation played little role in adaptation.