School of Languages and Linguistics - Research Publications
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ItemAcoustic analysis of the effects of 24 hours of sustained wakefulness(Australasian Speech Science and Technology Association, 2010)The effect of 24 hours of sustained wakefulness on the speech of healthy adults is poorly documented. Therefore, speech samples were systematically acquired (e.g., every four hours) from 18 healthy adults over 24 hours. Stimuli included automated and extemporaneous tasks, sustained vowel and a read passage. Measures of timing and frequency were derived acoustically using Praat and significant changes were observed on all tasks. The effect of fatigue on speech was found to be strongest just before dawn (after 22 hours). Key features of timing (e.g., mean pause length), frequency (e.g., F4 variation) and power (alpha ratio) changed as a function of increasing levels of fatigue. Index Terms: fatigue, voice, tiredness, clinical marker
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ItemNo Preview AvailableAcoustic analysis of the effects of sustained wakefulness on speech(ACOUSTICAL SOC AMER AMER INST PHYSICS, 2010-12)Exposing healthy adults to extended periods of wakefulness is known to induce changes in psychomotor functioning [Maruff et al. (2005). J. Sleep Res. 14, 21-27]. The effect of fatigue on speech is less well understood. To date, no studies have examined the pitch and timing of neurologically healthy individuals over 24 h of sustained wakefulness. Therefore, speech samples were systematically acquired (e.g., every 4 h) from 18 healthy adults over 24 h. Stimuli included automated and extemporaneous speech tasks, sustained vowel, and a read passage. Measures of timing, frequency and spectral energy were derived acoustically using PRAAT and significant changes were observed on all tasks. The effect of fatigue on speech was found to be strongest just before dawn (after 22 h). Specifically, total speech time, mean pause length, and total signal time all increased as a function of increasing levels of fatigue on the reading tasks; percentage pause and mean pause length decreased on the counting task; F4 variation decreased on the sustained vowel tasks /a:/; and alpha ratio increased on the extemporaneous speech tasks. These findings suggest that acoustic methodologies provide objective data on central nervous system functioning and that changes in speech production occur in healthy adults after just 24 h of sustained wakefulness.
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ItemNo Preview AvailableReliability, stability, and sensitivity to change and impairment in acoustic measures of timing and frequency(Elsevier Inc., 2011)Assessment of the voice for supporting classifications of central nervous system (CNS) impairment requires a different practical, methodological, and statistical framework compared with assessment of the voice to guide decisions about change in the CNS. In experimental terms, an understanding of the stability and sensitivity to change of an assessment protocol is required to guide decisions about CNS change. Five experiments (N=70) were conducted using a set of commonly used stimuli (eg, sustained vowel, reading, extemporaneous speech) and easily acquired measures (eg, f0–f4, percent pause). Stability of these measures was examined through their repeated application in healthy adults over brief and intermediate retest intervals (ie, 30 seconds, 2 hours, and 1 week). Those measures found to be stable were then challenged using an experimental model that reliably changes voice acoustic properties (ie, the Lombard effect). Finally, adults with an established CNS-related motor speech disorder (dysarthria) were compared with healthy controls. Of the 61 acoustic variables studied, 36 showed good stability over all three stability experiments (eg, number of pauses, total speech time, speech rate, f0–f4). Of the measures with good stability, a number of frequency measures showed a change in response to increased vocal effort resulting from the Lombard effect challenge. Furthermore, several timing measures significantly separated the control and motor speech impairment groups. Measures with high levels of stability within healthy adults, and those that show sensitivity to change and impairment may prove effective for monitoring changes in CNS functioning.
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ItemPhonetic cues to accentual prominence in Bengali English(City University of Hong Kong, 2011)This paper examines the acoustic correlates of accentual prominence in English spoken by L1 Bengali speakers. The acoustic phonetic correlates of stressed unaccented vowels, and stressed vowels produced in positions of narrow focus were compared. As observed for many varieties of English, the main correlates of accentual prominence in narrow focused contexts were presence of/and extent of f0 movement throughout the stressed vowel, followed by a concomitant increase in RMS-db. Vowels were also longer compared to stressed unaccented vowels although the differences were relatively small and highly variable.
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Item/æl/-/el/ transposition in Australian English: Hypercorrection or a competing sound change?(City University of Hong Kong, 2011)
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ItemDurational correlates of word-initial voiceless geminate stops: The case of Kelantan Malay(City University of Hong Kong, 2011)
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ItemA Taste of Prosody: Possible Effects of the Word-Initial Singleton-Geminate Contrast on Post-Consonantal Vowel Duration in Kelantan Malay(Tongji University Press, 2012-01-01)
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ItemAn acoustic analysis of release burst amplitude in the Kelantan Malay singleton/ geminate stop contrast(Australasian Speech Science and Technology Australia (ASSTA), 2012)
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ItemThe Effects of Prosodic Context and Word Position on Gupapuyngu Vowels(Tongji University Press, 2012-01-01)
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ItemVowel perception in Victoria: variability, confusability and listener expectation(Macquarie University, 2012)