An Experimental Study on Societal Factors Affecting VOT of English Plosives

Plosives are integral components of English consonants. In phonetics, English plosives are classified into voiceless plosives /p, t, k/ and /b, d, g/. VOT (voice onset time) was defined as “the time interval between the burst that marks release of the stop closure and the onset of quasi-periodicity that reflects laryngeal vibration”. VOT is a significant acoustic feature and analytic parameter of plosives. Referring to Labov’s experimental model of linguistic variation analysis, this study investigates the influences of societal factors have on the VOT of English plosives.In this study, 15 English words with word-initial voiceless plosives /p, t, k/ and 15 word-initial voiced plosives /b, d, g/ were selected as reading material; meanwhile, 30 subjects were randomly recruited to read, and audio samples were collected. It is found that the two social factors (gender and regional dialect) selected in this experiment have influences in different degrees on the English plosive VOT of the subjects. The specific results are as follows.For gender, no significant difference exists between males and females, but the mean VOT of females is longer than that of males, which is basically consistent with previous research results. The underlying reasons of the gender VOT differences inferred by this paper can be physiological and sociophonetical. For regional dialects, the VOT of the subjects were primarily influenced by Southwest Mandarin and Min Dialect, in which the mean value of voiceless plosives was higher and the difference was greater for speakers of Southwest Mandarin, and the mean value of voiced plosives was higher and the difference was greater for speakers of Min Dialect. The results of this empirical study theoretically provide some reference for acoustic researches, and pedagogically, provide some implications for optimizations of English curriculums in university

Louisiana State University nasalance protocol standardization

It was the purpose of this study to obtain nasalance values using the Nasometer and a resonance evaluation created at the Louisiana State University (LSU) Speech and Hearing Clinic. The Nasometer was used to measure the amount of nasal acoustic energy in the speech of 40 normal young adults during sustained vowel production, consonant vowel reduplications, and connected speech using the Rainbow Passage. Means and standard deviations are presented for the individual speech tasks and according to gender. Nasalance values for the sustained vowels were significantly higher for the high front vowel /i/ than any other vowel, and the lowest nasalance value was obtained by the high back vowel /u/. The vowels in order of highest to lowest nasalance values were as follows: /i, ae, a, u/. No significant gender differences were found for sustained vowel production or the Rainbow Passage. Correlation values indicated that three phonemes /u, k, g/ from the resonance protocol were the best predictors of nasalance for the reading passage. The results are discussed with regard to potential reasons why minimal gender differences were found, why the phonemes were found to be the best predictors of nasalance, and how the LSU protocol can be modified to provide a more effective and efficient resonance evaluation

The Application of Clear Speech in Electrolaryngeal Speakers

The present work was comprised of a series of experiments that investigated the application of clear speech (CS) in a group of electrolaryngeal (EL) speakers. Three experiments were conducted to assess the impact of CS on three important aspects of EL speech. More specifically, Experiment 1 sought to identify the impact of CS on EL speakers’ word and consonant intelligibility; Experiment 2 examined the influence of CS on the acoustic characteristics of words and vowels in EL speech; and finally, Experiment 3 sought to identify the influence of CS produced by EL speakers on auditory-perceptual ratings by naïve listeners. Results revealed that overall word and consonant intelligibility were minimally different when EL speakers used CS compared to their everyday, ‘habitual’ speech (HS) (Experiment 1). Secondly, EL speakers’ use of CS significantly increased word durations, but did not have a substantial impact on fundamental and formant frequency characteristics of vowels (Experiment 2). Finally, due to the productive changes associated with CS involving a slower rate of speech, over-articulation, and increased mouth-opening, listeners judged EL speech to be significantly less acceptable to listen to when compared to HS. However, no significant effect of speaking condition was noted on listeners’ comfort levels (Experiment 3). Overall, findings suggest that the acoustic deficits in EL speech might be too complex to derive further benefit from CS in the areas of speech intelligibility, the acoustic structure of EL speech and/or auditory-perceptual ratings of EL speakers. Clinical implications and future directions for research are discussed

An acoustic, aerodynamic and perceptual investigation of word-initial denasalization in Korean

Korean nasals /m/ and /n/ are generally considered by Korean phoneticians to be hardly different from the corresponding English sounds, but those in word-initial position are often perceived as plosives by native speakers of English. This had been noted by only a few previous observers, and investigated on a very limited scale. In this study, various experimental methods were employed in systematic analyses of the production and acoustic form of word-initial /m/ and /n/ from fluent connected speech collected from a relatively large number of informants, and corresponding perception tests were conducted with groups of Korean and English listeners. Auditory and spectrographic analyses confirmed that the segments were commonly “denasalized”. They display characteristics widely different from those of sonorant nasals, lacking the nasal formants commonly seen in spectrograms; in most cases they were more similar to voiced plosives, many tokens even showing plosive-like release bursts. Spectral analyses confirmed that denasalized nasals are significantly different from sonorant nasals throughout the whole frequency range but remain somewhat different from voiced plosives in the low and high frequency regions. Aerodynamic and accelerometer studies, which examined the consonants in CV combinations, indicated that the denasalized sounds are evidently produced with a pattern of velopharyngeal control which is different from those of sonorant nasals or of plosives. Perception tests showed overwhelmingly that the word-initial denasalized sounds are categorized as nasals by Korean listeners but as plosives by English listeners. When real voiced plosive tokens from another context are artificially moved to word-initial position, Koreans perceive these too as nasals, while English listeners’ responses are not sensitive to the context. The study shows that denasalization needs to be acknowledged as a major regular feature of spoken Korean, even though it has been largely ignored up to now. Directions for further research are outlined

Improved status following behavioural intervention in a case of severe dysarthria with stroke aetiology

There is little published intervention outcome literature concerning dysarthria acquired from stroke. Single case studies have the potential to provide more detailed specification and interpretation than is generally possible with larger participant numbers and are thus informative for clinicians who may deal with similar cases. Such research also contributes to the future planning of larger scale investigations. Behavioural intervention is described which was carried out with a man with severe dysarthria following stroke, beginning at seven and ending at nine months after stroke. Pre-intervention stability between five and seven months contrasted with significant improvements post-intervention on listener-rated measures of word and reading intelligibility and communication effectiveness in conversation. A range of speech analyses were undertaken (comprising of rate, pause and intonation characteristics in connected speech and phonetic transcription of single word production), with the aim of identifying components of speech which might explain the listeners’ perceptions of improvement. Pre- and post intervention changes could be detected mainly in parameters related to utterance segmentation and intonation. The basis of improvement in dysarthria following intervention is complex, both in terms of the active therapeutic dimensions and also the specific speech alterations which account for changes to intelligibility and effectiveness. Single case results are not necessarily generalisable to other cases and outcomes may be affected by participant factors and therapeutic variables, which are not readily controllable

Measurement of the VOT of voiceless plosives: multiple bursts in Western Andalusian Spanish

Multiple bursts (MBs) of plosives have been frequently reported but not sufficiently quantified. This study sought to examine experimentally MBs in a Spanish variety and to reveal the role of MBs when analyzing the VOT of voiceless plosives. 567 productions of /p t k/ by twenty-one speakers were analyzed. Findings indicated that two VOT measurement methods in the presence of MBs produced substantially different VOT values. MBs were also conditioned to different degrees by place of articulation, vowel height, and speech rate. This study has significant implications for research on VOT of voiceless plosives