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 (
A1–
P1), and the frequencies (in Hz) of the first formant (
F1) and extra peak (
Fp1). 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
F-ratio and by conducting regression analysis between two recording sessions, respectively. Results revealed that
Fp1 of front vowels yielded large
F-ratio values, which means high speaker-discriminating power and that
A1–
P1 of the vowels in oral contexts showed within-speaker stability over time.
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