Rhinolalia is altered speech caused by abnormal airflow through the nose during phonation. It may an organic or functional cause. While it is technically correct to distinguish between altered voice sounds (rhinophonia) and altered sound production (rhinolalia), both terms are often used interchangeably. Several types of rhinolalia are distinguished based on the voice sound . . . .
--Rudolf Probst, Gerhard Grevers and Heinrich Iro, 2006, Basic Otorhinolaryngology: a Step-by-step Learning Guide, 401