Nasalance and Nasometry

[Page 1219]A key distinguishing perceptual characteristic of speech and voice is resonance. In speech production, resonance refers to the vibration of air within the cavities of the vocal tract that occurs along with an initial sound source (e.g., the sound produced by vocal fold vibration). In addition, resonance is also used to describe the relative balance of sound energy conducted via the oral versus nasal cavities. In this context, resonance may be judged as normal, hypernasal, or hyponasal. Hypernasality refers to excessive nasal resonance during vowel and semivowel production due to atypical coupling of the oral and nasal cavities and may be due to structural and/or neurological differences or learning deficits. In contrast, hyponasality refers to a reduction or absence of expected nasal resonance during ...