ASA 124th Meeting New Orleans 1992 October

1pSP6. Teaching acoustic cues of nasal resonance.

Cathy Andrews

Dept. of Speech Commun., Penn State Univ., University Park, PA 16802

Acoustic coupling between the oral and nasal cavities results in the addition of pole-zero pairs to the vocal-tract transfer function, which interacts with variations in vocal-tract shaping across different vowels and speakers. Presentation of the myraid of acoustic features associated with nasalization based on vocal-tract models can confuse students with little mathematical background. One successful approach allows students to discover a few established cues via waveform and spectrographic analysis. Broadband spectrograms of students' productions of ``bead--bean'' clearly illustrate a nasal murmur (200--300 Hz) and the attenuation of formant frequencies is the nasalized vowel compared to the oral vowel. Another broadband spectrogram is made of the tape-recorded speech of a female speaker of Texan English, exhibiting extreme attenuation in the F1 region. The decreased intensity of the nasalized vowel in ``bean'' (compared to the oral vowel in ``bead'') is seen as rounded waveform cycles with lower amplitude using waveform-editing software. Changes in vowel quality due to nasalization can be heard as the students proceed screen-by-screen through the waveform.