Acoustic characteristics of the vowel systems of six regional varieties of American English.
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Previous research by speech scientists on the acoustic characteristics of American English vowel systems has typically focused on a single regional variety, despite decades of sociolinguistic research demonstrating the extent of regional phonological variation in the United States. In the present study, acoustic measures of duration and first and second formant frequencies were obtained from five repetitions of 11 different vowels produced by 48 talkers representing both genders and six regional varieties of American English. Results revealed consistent variation due to region of origin, particularly with respect to the production of low vowels and high back vowels. The Northern talkers produced shifted low vowels consistent with the Northern Cities Chain Shift, the Southern talkers produced fronted back vowels consistent with the Southern Vowel Shift, and the New England, Midland, and Western talkers produced the low back vowel merger. These findings indicate that the vowel systems of American English are better characterized in terms of the region of origin of the talkers than in terms of a single set of idealized acoustic-phonetic baselines of "General" American English and provide benchmark data for six regional varieties. (+info)
Production and perception of clear speech in Croatian and English.
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Previous research has established that naturally produced English clear speech is more intelligible than English conversational speech. The major goal of this paper was to establish the presence of the clear speech effect in production and perception of a language other than English, namely Croatian. A systematic investigation of the conversational-to-clear speech transformations across languages with different phonological properties (e.g., large versus small vowel inventory) can provide a window into the interaction of general auditory-perceptual and phonological, structural factors that contribute to the high intelligibility of clear speech. The results of this study showed that naturally produced clear speech is a distinct, listener-oriented, intelligibility-enhancing mode of speech production in both languages. Furthermore, the acoustic-phonetic features of the conversational-to-clear speech transformation revealed cross-language similarities in clear speech production strategies. In both languages, talkers exhibited a decrease in speaking rate and an increase in pitch range, as well as an expansion of the vowel space. Notably, the findings of this study showed equivalent vowel space expansion in English and Croatian clear speech, despite the difference in vowel inventory size across the two languages, suggesting that the extent of vowel contrast enhancement in hyperarticulated clear speech is independent of vowel inventory size. (+info)
A methodology for assessing the functions of emerging speech in children with developmental disabilities.
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An approach based on Skinner's (1957) theory of verbal behavior has been developed to understand and teach elementary communication skills to children with autism and developmental disabilities (Sundberg & Partington, 1998). However, few studies have directly examined the characteristics of emerging language in children with developmental disabilities. The purpose of this study was to develop and evaluate an assessment for identifying the elementary functions of vocal speech in children. Participants were 4 children with developmental disabilities, aged 6 years to 12 years, who exhibited at least one distinguishable vocal response (word or phrase) frequently in the natural environment. The assessment focused on three verbal operants delineated by Skinner (mand, tact, and intraverbal). One or more functions were identified for at least one vocal response of each child. Results suggested that this assessment would be useful for (a) evaluating Skinner's theory, (b) guiding decisions about language training for individual children, and (c) studying the nature of expressive language development in children with developmental disabilities. (+info)
The effect of age at cochlear implant initial stimulation on expressive language growth in infants and toddlers.
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This study examined the growth of expressive language skills in children who received cochlear implants (CIs) in infancy. Repeated language measures were gathered from 29 children who received CIs between 10 and 40 months of age. Both cross-sectional and growth curve analyses were used to assess the relationship between expressive language outcomes and CI experience. A beneficial effect of earlier implantation on expressive language growth was found. Growth curve analysis showed that growth was more rapid in children implanted as infants than those implanted as toddlers. Age at initial stimulation accounted for 14.6% of the variance of the individual differences in expressive language growth rates. (+info)
Left-hemispheric dominance for articulation: a prospective study on acute ischaemic dysarthria at different localizations.
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Dysarthria is a frequent symptom in cerebral ischaemia. However, speech characteristics of these patients have not previously been investigated in relation to lesion site in a prospective study. We investigated the auditory perceptual features in 62 consecutive patients with dysarthria due to a single, non-space-occupying cerebral infarction confirmed by MRI. Standardized speech samples of all patients were stored within 72 h after stroke onset using a digital tape recorder. Speech samples were assessed independently by two experienced speech therapists, who were unaware of the clinical and neuroradiological findings, using an interval scale ranging from 0 to 6. Separately assessed were features of articulation, phonation, prosody, and the global severity for a total of 31 items. Extracerebellar infarctions (85.5%) were located in the lower motor cortex (14.5%), striatocapsular region (46.8%) and base of the pons (24.2%). Isolated cerebellar infarctions were present in 14.5% of patients. There was a strong correlation between the findings of both examiners, showing identical scores, or only minor differences (<1 on the assessment scale) for 80% of all items. The average severity of dysarthria was 2.9 +/- 1.3. Articulatory abnormalities were the predominant deviation characteristics, affecting in particular the production of consonants. However, phonatory and prosodic abnormalities were also frequently observed speech characteristics. As revealed by factor analysis of speech characteristics the total severity of dysarthria was mainly influenced by the impairment of articulation. Speech parameters describing characteristics of articulation and prosody showed significant side-to-side and area differences, while this effect was lacking for any voice parameter. Left cerebral lesions showed a more severe overall impairment of speech and articulation, independent of lesion topography. Thirty-eight of 62 patients were available for follow-up. Speech evaluation showed normal speech within weeks in 15 out of 38 patients (39.5%). In the other 23 patients overall severity of dysarthria was mild. This is the first prospective study which describes speech characteristics of dysarthria due to acute unilateral cerebral infarctions. We could demonstrate that dysarthria in extracerebellar infarctions was more frequently caused by left-sided lesions and that the severity of dysarthria was more pronounced in left-sided lesions independent from lesion topography. All extracerebellar lesions were located along the course of the cortico-bulbar tract fibres. Compatible with a common pathophysiological basis of dysarthria in these patients, none of the 31 speech items differed significantly between subcortical and brainstem lesions. (+info)
Variation within dialects: a case of Cajun/Creole influence within child SAAE and SWE.
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PURPOSE: This study examined whether child speakers of Southern African American English (SAAE) and Southern White English (SWE) who were also perceived by some listeners to present a Cajun/Creole English (CE) influence within their dialects produced elevated rates of 6 phonological and 5 morphological patterns of vernacular relative to other SAAE- and SWE-speaking children. METHOD: A group comparison design was followed. The data were listener judgments, 1-min audiotaped excerpts of conversational speech, and transcribed language samples from 93 children (31 classified as specifically language impaired while the others were classified as either aged-matched or language-matched controls; 13 classified as SWE with CE, 40 classified as SWE only, 18 classified as SAAE with CE, and 22 classified as SAAE only). RESULTS: Results indicated that children with a CE influence produced elevated rates of vernacular phonology relative to the others, with 2 patterns (nonaspirated stops and glide reduction) showing statistically significant group differences. In contrast, the children's use of vernacular morphology was unrelated to their CE status, but was instead related to their primary dialect (SWE vs. SAAE) and language ability classification (impaired vs. normal). CONCLUSIONS: The findings highlight the role of phonology in listeners' perceptions of dialect variation within 2 nonmainstream dialects (SWE and SAAE). The findings also demonstrate the ways phonological and morphological forms of vernacular can be independently influenced by different types of child variables. (+info)
Analysis of fundamental frequency, jitter, shimmer and vocal intensity in children with phonological disorders.
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Phonological Disorder is a disturbance of primary manifestation of undefined causes that makes speech become unintelligible. The analysis of vocal parameters becomes important in the process of diagnosis of this disorder, since voice disorders could interfere in the production of speech sounds. AIM: The objective of this study was to verify vocal characteristics related to the intensity and fundamental frequency--F0--and their disturbance indexes--jitter and shimmer--in children with phonological disorders. STUDY DESIGN: Clinical prospective with transversal cohort. MATERIAL AND METHOD: There were 40 children, 20 of them with phonological disorders and 20 with no speech and language disturbances. Phonological exams with the ABFW infantile language test and spontaneous speech were applied. The Computer Speech Lab was used to record and perform acoustic analyses of the vowels /a/, /e/, /i/, through the vocal parameters: fundamental frequency, intensity, jitter and shimmer. RESULTS: F0--vowel /e/ was smaller, on average, in the Phonological Disorder Group and it was 126 Hz in the Control Group. To shimmer and jitter there was no evidence that the means of the Phonological Disorder Group were different from the ones of the Control Group (p= 0.191, p= 0.865, respectively). As for intensity, there was evidence that the average did not differ in the Phonological Disorder Group and the Control Group (p= 0.002). CONCLUSION: The frequency of the vowel /e/ was smaller in the Phonological Disorder Group. There was difference between the two groups regarding the means of intensity of vowels /a/, /e/ and /i/, smaller in the Phonological Disorder Group. No differences between the groups were found regarding the averages of jitter and shimmer. (+info)
Disruption of sitting balance after stroke: influence of spoken output.
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OBJECTIVES: To identify the extent of dual task interference between cognitive and motor tasks, (cognitive motor interference (CMI)) in sitting balance during recovery from stroke; to compare CMI in sitting balance between stroke and non-stroke groups; and to record any changes to CMI during sitting that correlate with functional recovery. METHOD: 36 patients from stroke rehabilitation settings in three NHS trusts. Healthy control group: 21 older volunteers. Measures of seated postural sway were taken in unsupported sitting positions, alone, or concurrently with either a repetitive utterance task or an oral word category generation task. Outcome measures were variability of sway area, path length of sway, and the number of valid words generated. RESULTS: Stroke patients were generally less stable than controls during unsupported sitting tasks. They showed greater sway during repetitive speech compared with quiet sitting, but did not show increased instability to posture between repetitive speech and word category generation. When compared with controls, stroke patients experienced greater dual task interferences during repetitive utterance but not during word generation. Sway during repetitive speech was negatively correlated with concurrent function on the Barthel ADL index. CONCLUSIONS: The stroke patients showed postural instability and poor word generation skills. The results of this study show that the effort of verbal utterances alone was sufficient to disturb postural control early after stroke, and the extent of this instability correlated with concomitant Barthel ADL function. (+info)