Final answer:
Hypernasality occurs when vowels or voiced consonants are nasalized due to an early or prolonged opening of the velopharyngeal port, causing speech to have a nasal quality.
Step-by-step explanation:
When vowels or voiced consonants are nasalized due to an early opening or prolonged opening of the velopharyngeal port, the condition is referred to as Hypernasality. The velopharyngeal port usually closes off the nasal passages during the production of vowels and most consonants. In hypernasality, however, this closure is incomplete, allowing air to escape through the nasal cavity, which can make speech sound nasal.
The nasal conchae and various parts of the nasal cavity structure, like the nares, the nasal septum, and the paranasal sinuses, play essential roles in the tone and quality of voice. Under normal circumstances, their structure maximizes the efficiency of the air we breathe and the sound of our voice. But when hypernasality occurs, it can affect the normal resonance, which should be mostly oral for vowels and many consonants, giving it a nasal quality.