We present an unusual cause of rhinolalia clausa secondary to an oropharyngeal mass. A 69-year-old male presented to the otorhinolaryngology clinic with a one year history of a ‘plummy’ voice. He had a longstanding history of severe ankylosing spondylitis. Examination revealed an obvious hyponasal voice and a smooth hard mass in the midline of the posterior nasopharyngeal and oropharyngeal walls. Subsequent computed tomography scans and lateral plain neck X-ray showed a fracture dislocation of the odontoid peg, secondary to ankylosing spondylitis, which had eroded through the body of the C1 vertebra to lie anteriorly, resulting in the aforementioned impression into the pharyngeal mucosa. The radiological images, the role of the nasal airways in phonation and the causes of hyponasal speech are discussed.