School of Languages and Linguistics - Research Publications
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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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ItemThe acoustic characteristics of diphthongs in Indian English(Wiley, 2010-01-01)This paper presents the results of an acoustic analysis of English diphthongs produced by three L1 speakers of Hindi and four L1 speakers of Punjabi. Formant trajectories of rising and falling diphthongs (i.e., vowels where there is a clear rising or falling trajectory through the F1/F2 vowel space) were analysed in a corpus of citation-form words. In line with previous research, the diphthong inventory included six different diphthongs and a long monophthongal vowel [OI] in place of/partial derivative U/in GOAT; however, none of the speakers produced a full set of diphthong vowels. In addition, the/eI/diphthong, as in FACE, and the/U partial derivative/diphthong, as in TOUR, had both monophthongal and diphthongal realizations depending on the speaker. Overall, there was a great deal of variation in diphthong realization across the corpus but L1 appeared to be a relevant factor. Punjabi speakers showed a wider range of phonetic realizations for some of the vowels, and were more likely to produce long monophthongs rather than diphthongs. The results also highlight differences in the phonetic characteristics of several diphthongs between the speakers of two language backgrounds. The results of this study therefore contribute to the debate on the phonemic representation of IE vowels by taking into account different L1 influence (i.e., Hindi or Punjabi).
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ItemBig words, small phrases: Mismatches between pause units and the polysynthetic word in Dalabon(Mouton de Gruyter, 2008)This article uses instrumental data from natural speech to examine the phenomenon of pause placement within the verbal word in Dalabon, a polysynthetic Australian language of Arnhem Land. Though the phenomenon is incipient and in two sample texts occurs in only around 4% of verbs, there are clear possibilities for interrupting the grammatical word by pause after the pronominal prefix and some associated material at the left edge, though these within-word pauses are significantly shorter, on average, than those between words. Within-word pause placement is not random, but is restricted to certain affix boundaries; it requires that the paused-after material be at least dimoraic, and that the remaining material in the verbal word be at least disyllabic. Bininj Gun-wok, another polysynthetic language closely related to Dalabon, does not allow pauses to interrupt the verbal word, and the Dalabon development appears to be tied up with certain morphological innovations that have increased the proportion of closed syllables in the pronominal prefix zone of the verb. Though only incipient and not yet phonologized, pause placement in Dalabon verbs suggests a phonology-driven route by which polysynthetic languages may ultimately become less morphologically complex by fracturing into smaller units.
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ItemNo Preview AvailableFactors affecting the acquisition of vowel phonemes by pre-linguistically deafened cochlear implant users learning Cantonese(Taylor & Francis Ltd, 2006-11-01)This paper describes the development of vowel inventories in 12 pre-linguistically deafened Cantonese-speaking cochlear implant users. The aim of the research was to understand the role of linguistic, perceptual and articulatory factors in determining the rate and order of vowel acquisition in this population of children. Rate and order of vowel acquisition were reported against two criteria. The "targetless" criterion for production required at least two correct productions of a vowel in a sample of speech. The second or "target" criterion required that a vowel first met the targetless criterion and was further produced correctly in the appropriate phonological context at least 50% of the time. Factors associated with articulatory difficulty were shown to explain the composition of pre-implant vowel inventories. Subsequent to receiving an implant, all children demonstrated a steady and systematic expansion in the size of their vowel inventories though the rate of acquisition varied between individuals. The order of vowel acquisition was affected by a combination of linguistic and articulatory factors. The paper concludes by discussing the clinical implications of these findings for helping children develop good spoken language skills subsequent to receiving an implant.