Objective: The purpose of this study is to determine whether a novel, user-friendly rating system, visual sort and rate (VSR) provides comparable ratings to the currently used direct magnitude estimation (DME) rating system for rating perceptions of audible nasal emission (ANE) and hypernasality in cleft palate speakers. Methods: Twelve naïve listeners rated 152 speech samples of speakers with cleft palate across four conditions: rating hypernasality and ANE using either a VSR or DME rating scale. Raters were provided with a short training session, prior to rating each day. Inter- and intra-rater reliabilities, as well the line of best fit between scores using VSR and scores using DME was calculated to determine usability of VSR as a novel rating system. Results: Direct magnitude estimation resulted in the highest levels of inter-rater reliability, when rating hypernasality (DME r= .48; VSR r=.14), as well as ANE (DME r= .27; VSR r=.15). Most raters demonstrated high intra-rater reliabilities across conditions. A curvilinear line of best fit most accurately captured the relationship between DME and VSR scores when rating hypernasality (r=.64) and ANE (r=.66). Conclusions: A curvilinear relationship between ratings suggests that both variables are prothetic, and therefore, best captured using a DME rating scale (Eadie & Doyle, 2002). The use of DME is supported for continued use rating hypernasality, even amongst naïve listeners given a training session. Rating ANE was difficult, as ratings yielded low inter-rater reliabilities, regardless of the scale used. Further research regarding perceptions of audible nasal emission is warranted.

Second language (L2) learners of English must learn to produce English phonemes, words, and sentences. These L2 learners make many errors when learning English; they may change the place or manner of articulation, insert vowels, or delete consonants. Obstruent sounds, such as fricatives, affricates, and stops, can be especially difficult for L2 learners. This study analyzed native English speakers<'> perception of the quality of obstruents produced by native Mandarin Chinese and Korean speakers. Target words containing obstruents had been produced in three different tasks: in a carrier phrase, in a paragraph, and in a spontaneous speech sample. Obstruents were produced in word-initial position and word-final position. Raters with differing levels of expertise listened to these words and rated the perceptual quality of the obstruents within the words. This study found that overall, English obstruent productions by native Mandarin and Korean L2 speakers learning English were rated most clear when produced in word-initial position in a carrier phrase or a paragraph. The lowest ratings given were of obstruents in word-final position in spontaneous speech. No significant differences were found for listener expertise level. Combined with future research, results from this study will help educate the field of second language instruction as to how the speech of Korean and Mandarin learners of English is perceived. It also provides additional information on the effect that listener expertise has on the judgment of L2 speech production.

The technique of �open throat� is a pedagogical concept transmitted through the oral tradition of singing. This thesis explored the pedagogical perceptions and practices of �open throat� using empirical methodologies to assess technical skill and associated vocal quality. In the first study (Mitchell, Kenny, Ryan, & Davis, 2003), we assessed the degree of consensus amongst singing pedagogues regarding the definition of, and use in the singing studio of the technique called �open throat.� Results indicated that all fifteen pedagogues described �open throat� technique as fundamental to singing training and were positive about the sound quality it achieved, especially in classical singing. It was described as a way of maximising pharyngeal space or abducting the false vocal folds. Hypotheses generated from pedagogical beliefs expressed in this first study were then tested acoustically (Mitchell & Kenny, 2004a, 2004b). Six advanced singing students sang in two conditions: �optimal� (O), using maximal open throat, �sub-optimal� (SO), using reduced open throat and loud sub-optimal (LSO) to control for the effect of loudness. From these recordings, acoustic characteristics of vibrato (Mitchell & Kenny, 2004b) and energy distribution (Mitchell & Kenny, 2004a) were examined. Subsequent investigations of the vibrato parameters of rate, extent and onset, revealed that extent was significantly reduced and onset increased when singers did not use the technique. As inconsistent vibrato is considered indicative of poor singing, it was hypothesized that testing the energy distribution in these singers� voices in each condition would identify the timbral changes associated with open throat. Visual inspection of long term average spectra (LTAS) confirmed differences between O and SO, but conventional measures applied to long term average spectra (LTAS), comparing energy peak height [singing power ratio (SPR)] and peak area [energy ratio (ER)] were not sensitive to the changes identified through visual inspection of the LTAS. These results were not consistent with the vibrato findings and suggest that conventional measures of SPR and ER are not sufficiently sensitive to evaluate LTAS. In the fourth study, fifteen expert listeners consistently and reliably identified the presence of open throat technique with 87% accuracy (Mitchell & Kenny, in press). In the fifth study, LTAS measurements were examined with respect to the perceptual ratings of singers. There was no relationship between perceptual rankings of vocal beauty and acoustic rankings of vocal quality (Kenny & Mitchell, 2004, in press). There is a vast literature of spectral energy definitions of good voice but the studies in this thesis have indicated that current acoustic methods are limited in defining vocal quality. They also suggest that current work in singing has not sufficiently incorporated perceptual ratings and descriptions of sound quality or the relationship between acoustic and perceptual factors with pedagogical practices.

The need for a standard approach for the diagnosis of speech disorders, in particular resonance disorders associated with cleft lip and/or palate, has been recognised. A reliable and valid measure of nasality is important, because it not only affects clinical decision making but is also essential for the evaluation of treatment outcomes. In order to allow cross-linguistic comparisons of the assessment of resonance, language specific stimuli developed according to a common set of guidelines have been recommended. The aim of this thesis was to contribute to the development of an assessment protocol for use in Malay speaking individuals with clefts of the lip and/or palate, specifically focusing on the detection of nasality. A series of four studies were completed which systematically developed and then validated a set of stimuli in the Malay language using both perceptual and instrumental measures. / In the first study, three stimuli were developed for the assessment of nasality based on both the proportion of nasal phonemes in typical conversation samples in Malay and guidelines from the current international literature. The phonetic content of the stimuli were comparable to similar passages used in English and comprised of an Oral Passage, a Nasal Passage and a Set of Sentences. / In the second study, the stimuli constructed were tested in a large number of typically developing (non-cleft) Malay speaking children using both instrumental and perceptual methods of assessment. The results of this study provide the first set of normative data of nasalance scores for the three newly developed stimuli. The mean nasalance score for the Oral Passage was 13.86% (SD = 5.11, 95% CI = 13.04–14.68), 60.28% (SD = 6.99, 95% CI = 59.15–61.41) for the Nasal Passage, and 27.72% (SD = 4.74, 95% CI = 26.96–28.49) for the Set of Sentences. These scores were significantly different from each other suggesting that they can be used to detect the different types of resonance disorder in speech (e.g. hypernasality and/or hyponasality). / In the third study, the stimuli were validated in a sample of Malay speaking children with cleft of the lip and/or palate and compared with a control population. Nasality was measured using perceptual evaluation and nasometry. The results suggested that the Oral Passage and Set of Sentences developed in Malay were valid measures for detecting hypernasality for both perceptual evaluation of nasality, and for nasometry. Due to the small number of participants that were hyponasal, the validity of the Nasal Passage could not be determined. / For nasometry to be clinically relevant threshold values that indicate abnormal nasality are required. The threshold values for each of the stimuli were first ascertained after obtaining typical nasality levels from a group of healthy Malay speaking children and then tested in a sample of cleft and non-cleft Malay speaking children. In contrast to the nasalance cutoffs obtained from typical Malay speaking children, the cutoffs obtained from the cleft children yielded better outcomes for detecting resonance disorders. The cutoffs were: ≥ 22% for the Oral Passage (sensitivity = 0.91, specificity = 0.93, overall efficiency = 0.92), ≥ 30% for the Set of Sentences (sensitivity = 0.96, specificity = 0.85, overall efficiency = 0.88) and ≤ 39 on the Nasal Passage (sensitivity = 1.00, specificity = 0.99, overall efficiency = 0.99). / Finally, the fourth study explored the application of recently developed techniques for assessing nasality using spectral voice analysis and compared these results with nasometry using a sub-sample of Malay speaking children from the third study. The participants were children with cleft lip and/or palate with perceived hypernasality and a group of healthy controls perceived to have normal resonance. The potential of assessing nasality using vowels, which ideally can be an easier option to administer clinically and have minimal impact on language and literacy skills, were investigated. / The findings showed that only the one-third-octave analysis method could be successfully used to detect hypernasality in the cleft population compared to the VLHR method. Using the one-third-octave analysis, the spectral characteristics of nasalised vowel /i/ taken from /pit/ and /tip/ showed an increase in amplitude in F1, between F1 and F2 regions. The amplitude of the formants at F3 region was lower in the cleft group but did not differ from the control group as reported in previous studies. Although, the one-third-octave analysis has some potential in detecting hypernasality, the accuracy of the analysis compared to perceptual ratings of nasality was only moderate. Compared to nasometry, the diagnostic value of the one-third-octave analysis in detecting hypernasality was lower. / The overall findings suggest that, except for the Nasal Passage, the Oral Passage and the Set of Sentences developed in Malay using this systematic approach were culturally appropriate and valid for the assessment of nasality. Furthermore, by comparing two instrumental methods (nasometry and spectral analysis) with perceptual evaluation in a large number of cleft and typically developing children, the present thesis was able to demonstrate the clinical benefits of two recently proposed methods of spectral voice analyses and compare them to existing methods. Compared to spectral analysis, nasometry remains a superior method for assessing nasality. Threshold values that indicate abnormal nasality levels for the newly developed stimuli in Malay have been recommended.

The technique of �open throat� is a pedagogical concept transmitted through the oral tradition of singing. This thesis explored the pedagogical perceptions and practices of �open throat� using empirical methodologies to assess technical skill and associated vocal quality. In the first study (Mitchell, Kenny, Ryan, & Davis, 2003), we assessed the degree of consensus amongst singing pedagogues regarding the definition of, and use in the singing studio of the technique called �open throat.� Results indicated that all fifteen pedagogues described �open throat� technique as fundamental to singing training and were positive about the sound quality it achieved, especially in classical singing. It was described as a way of maximising pharyngeal space or abducting the false vocal folds. Hypotheses generated from pedagogical beliefs expressed in this first study were then tested acoustically (Mitchell & Kenny, 2004a, 2004b). Six advanced singing students sang in two conditions: �optimal� (O), using maximal open throat, �sub-optimal� (SO), using reduced open throat and loud sub-optimal (LSO) to control for the effect of loudness. From these recordings, acoustic characteristics of vibrato (Mitchell & Kenny, 2004b) and energy distribution (Mitchell & Kenny, 2004a) were examined. Subsequent investigations of the vibrato parameters of rate, extent and onset, revealed that extent was significantly reduced and onset increased when singers did not use the technique. As inconsistent vibrato is considered indicative of poor singing, it was hypothesized that testing the energy distribution in these singers� voices in each condition would identify the timbral changes associated with open throat. Visual inspection of long term average spectra (LTAS) confirmed differences between O and SO, but conventional measures applied to long term average spectra (LTAS), comparing energy peak height [singing power ratio (SPR)] and peak area [energy ratio (ER)] were not sensitive to the changes identified through visual inspection of the LTAS. These results were not consistent with the vibrato findings and suggest that conventional measures of SPR and ER are not sufficiently sensitive to evaluate LTAS. In the fourth study, fifteen expert listeners consistently and reliably identified the presence of open throat technique with 87% accuracy (Mitchell & Kenny, in press). In the fifth study, LTAS measurements were examined with respect to the perceptual ratings of singers. There was no relationship between perceptual rankings of vocal beauty and acoustic rankings of vocal quality (Kenny & Mitchell, 2004, in press). There is a vast literature of spectral energy definitions of good voice but the studies in this thesis have indicated that current acoustic methods are limited in defining vocal quality. They also suggest that current work in singing has not sufficiently incorporated perceptual ratings and descriptions of sound quality or the relationship between acoustic and perceptual factors with pedagogical practices.

Second language (L2) learners of English must learn to produce English phonemes, words, and sentences. These L2 learners make many errors when learning English; they may change the place or manner of articulation, insert vowels, or delete consonants. Obstruent sounds, such as fricatives, affricates, and stops, can be especially difficult for L2 learners. This study analyzed native English speakers’ perception of the quality of obstruents produced by native Mandarin Chinese and Korean speakers. Target words containing obstruents had been produced in three different tasks: in a carrier phrase, in a paragraph, and in a spontaneous speech sample. Obstruents were produced in word-initial position and word-final position. Raters with differing levels of expertise listened to these words and rated the perceptual quality of the obstruents within the words. This study found that overall, English obstruent productions by native Mandarin and Korean L2 speakers learning English were rated most clear when produced in word-initial position in a carrier phrase or a paragraph. The lowest ratings given were of obstruents in word-final position in spontaneous speech. No significant differences were found for listener expertise level. Combined with future research, results from this study will help educate the field of second language instruction as to how the speech of Korean and Mandarin learners of English is perceived. It also provides additional information on the effect that listener expertise has on the judgment of L2 speech production.

As there is a clear correlation between one's degree of proficiency in the English language and one's subsequent financial compensation in the workplace setting and in interpersonal relationships, improving one's speaking abilities can be highly valuable from both a financial and emotional perspective. This study examines the efficacy of an electropalatography (EPG) assisted pronunciation training program in helping native Japanese learners of English acquire and improve the /r/ and /l/ sound contrast in American English, as rated by a group of listeners. Additionally, it evaluates whether or not the degree of improvement varied across word position, task type, or assessment period. Four native Japanese speaking learners of English participated in a four-week program which included seven 45- minute training sessions enhanced with visual biofeedback from the EPG. Samples of their productions of the target phonemes were obtained at baseline, at posttreatment, and at follow-up assessment periods. Using a visual analogue scale, 36 adult listeners listened to these recordings and provided comparative auditory perceptual ratings. Overall, subjects showed greater improvement in their production of the phoneme /l/ than in the phoneme /r/. Phoneme-specific patterns emerged in terms of word position, task type, and assessment period. For the phoneme /l/, more improvement was seen in final position than initial position, more improvement was seen in nonsense syllables than in words, and improvements were maintained across posttreatment to follow-up assessment periods. For the phoneme /r/, roughly equal levels of improvement were seen across word position, while greater improvement was seen in the context of words in sentences than in nonsense syllables, and posttreatment showed greater levels of improvement than did follow-up assessment periods. These results are promising as it indicates that EPG assisted pronunciation training may be an effective vehicle to help L2 English language learners acquire and improve their productions of the /r/-/l/ phonemic contrast. This is significant, as the Japanese L2 population has typically been found to be highly resistant to more traditional forms of intervention.

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