Final answer:
Patients perceived as having hypernasality produce high nasal airflow due to excessive nasal resonance during speech. This is often associated with velopharyngeal insufficiency, where the velopharyngeal valve does not close properly.
Step-by-step explanation:
Patients who produce high nasal airflow are perceived as having hypernasality. This condition occurs when there is excessive nasal resonance during speech due to increased airflow through the nasal cavity, often because of issues with the velopharyngeal mechanism. When the velopharyngeal valve does not close completely, it allows air to escape through the nose instead of the mouth during the production of certain speech sounds, particularly vowels and voiced consonants. This can be a characteristic of speech in conditions such as velopharyngeal insufficiency (VPI), where there is an inadequate closure of the velopharyngeal sphincter, but hypernasality specifically refers to the perceived nasal sound quality of the speech.