Speaker characteristics that appear in vowel nasalisation and their change over time
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This study was designed to evaluate whether or not previously proposed acoustic measures of vowel nasality are applicable for speaker comparison in a forensic context. Three acoustic parameters were selected and analysed for vowels in nasal and oral phonetic environments: the amplitude difference (in dB) between the first formant and the extra peak caused by nasalisation (<I>A1</I>–<I>P1</I>), and the frequencies (in Hz) of the first formant (<I>F1</I>) and extra peak (<I>Fp1</I>). We analysed eighteen monosyllables and six isolated words uttered by fifty male speakers and recorded through a microphone. Recordings were conducted twice for each speaker at a two to five month interval. Between- and within-speaker variations were examined using the <I>F</I>-ratio and by conducting regression analysis between two recording sessions, respectively. Results revealed that <I>Fp1</I> of front vowels yielded large <I>F</I>-ratio values, which means high speaker-discriminating power and that <I>A1</I>–<I>P1</I> of the vowels in oral contexts showed within-speaker stability over time.
- Acoustical Science and Technology
Acoustical Science and Technology 33(2), 96-105, 2012
ACOUSTICAL SOCIETY OF JAPAN