I. Velopharyngeal dysfunction occurs when the velopharyngeal valve does not properly close during speech, causing hypernasality and other speech issues. It can be caused by structural abnormalities (insufficiency), neurological/muscular issues (incompetence), or improper learning of speech sounds (mislearning). Successful treatment requires a team approach including surgeons, speech therapists, and other specialists to precisely diagnose the cause and customize treatment.