Temporal characteristics of nasalization in children and adult speakers of American English and Korean during production of three vowel contexts

Effect of vowel context on test-retest nasalance score variability in children with and without cleft palate

OBJECTIVE

The purpose of this study was to determine whether test-retest nasalance score variability differs between Korean children with and without cleft palate (CP) and vowel context influences variability in nasalance score.

PARTICIPANTS

Thirty-four 3-to-5-year-old children with and without CP participated in the study.

METHODS

Three 8-syllable speech stimuli devoid of nasal consonants were used for data collection. Each stimulus was loaded with high, low, or mixed vowels, respectively. All participants were asked to repeat the speech stimuli twice after the examiner, and an immediate test-retest nasalance score was assessed with no headgear change.

RESULTS

Children with CP exhibited significantly greater absolute difference in nasalance scores than children without CP. Variability in nasalance scores was significantly different for the vowel context, and the high vowel sentence showed a significantly larger difference in nasalance scores than the low vowel sentence. The cumulative frequencies indicated that, for children with CP in the high vowel sentence, only 8 of 17 (47%) repeated nasalance scores were within 5 points.

CONCLUSIONS

Test-retest nasalance score variability was greater for children with CP than children without CP, and there was greater variability for the high vowel sentence(s) for both groups.

Nasalance scores for normal Korean-speaking adults and children: Effects of age, vowel context, and stimulus length

OBJECTIVES

The purpose of this study was to collect nasalance scores for normal Korean-speaking children and adults and to determine whether age, vowel contexts, and stimulus length influence nasalance scores.

METHODS

Fifty-seven children aged 4-6 years and 17 adults participated in the study. Mean nasalance scores were obtained for eight sentences devoid of nasal consonants divided into the vowel/a/and/i/contexts; the sentences consisted of 4, 8, 16, and 31 syllables. All subjects were asked to repeat the speech stimuli twice after the examiner. The headset of the nasometer was replaced between the first and second recordings. An average value of the nasalance scores from the two recordings for each stimulus was calculated and used in the statistical analysis as a representative measure for each subject.

RESULTS

Mean and standard deviations of nasalance scores were obtained for each speech stimulus and each age group. The statistical analysis indicated significant effects of age and vowel context and a significant interaction between age and the vowel context on nasalance scores. However, the effect of stimulus length on nasalance scores was not significant. All speakers had higher nasalance scores for the vowel/i/contexts than for the vowel/a/contexts. Adults had higher nasalance scores compared to children in both vowel contexts.

CONCLUSIONS

These normal nasalance values from Korean-speaking children aged 4-6 years will provide important reference information for resonance assessment of children with cleft palate who have been considered for secondary palatal surgery. The results of the study suggest that subjects' age and the vowel content of speech stimuli should be carefully considered when interpreting the nasalance scores.

Temporal characteristics of nasalization in Persian speaker children with and without cleft palate

OBJECTIVES

The purpose of this study was to measure and compare temporal patterns of nasalization in Persian children with and without cleft palate in three vowel contexts.

METHODS

A Sample of 14 children with repaired cleft palates with or without cleft lip with moderate to severe hyper nasality and 14 children without cleft palate was chosen as subjects. The subjects were chosen from the ages of 4 to 12 years. The nasal onset interval, nasal offset interval and total nasalization duration were obtained from acoustic waveforms and spectrograms in three vowel contexts using Praat Software. For eliminating the effect of different speed of speech in the cleft palate group and control group, the ratio of nasalization duration was calculated.

RESULTS

Total nasalization duration are demonstrated by acoustic signals which shows the total significant different temporal patterns in children with cleft palate and without cleft palate and across the vowel contexts (P<0.000).

CONCLUSIONS

Longer nasalization durations in children with cleft palate in comparison to children without cleft palate show the delayed or deviant temporal patterns in children with cleft palate. The duration of nasalization reflecting temporal patterns of the oral-nasal acoustic impedance in children with cleft palate may have an influence on the perception of hyper nasality.

Comparison of nasal acceleration and nasalance across vowels

PURPOSE

The purpose of this study was to determine the performance of normalized nasal acceleration (NNA) relative to nasalance as estimates of nasalized versus nonnasalized vowel and sentence productions.

METHOD

Participants were 18 healthy speakers of American English. NNA was measured using a custom sensor, and nasalance was measured using the KayPentax Nasometer II. Speech stimuli consisted of CVC syllables with the vowels (//, /æ/, /i/, /u/) and sentences loaded with high front, high back, low front, and low back vowels in both nasal and nonnasal contexts.

RESULTS

NNA showed a small but significant effect of the vowel produced during syllable stimuli but no significant effect of vowel loading during sentence stimuli. Nasalance was significantly affected by the vowel being produced during both syllables and sentences with large effect sizes. Both NNA and nasalance were highly sensitive and specific to nasalization.

CONCLUSIONS

NNA was less affected by vowel than nasalance. Discrimination of nasal versus nonnasal stimuli using NNA and nasalance was comparable, suggesting potential for use of NNA for biofeedback applications. Future work to improve calibration of NNA is needed to lower intersubject variability.

Temporal characteristics of nasalization in speakers with and without cleft palate

OBJECTIVE

The purposes of the study were to compare the temporal characteristics of nasalization between speakers with cleft palate with or without cleft lip and normal adult speakers and to investigate the relationship between acoustic temporal measures and perceived nasality.

METHODS

Fifteen speakers with cleft palate with or without cleft lip and 15 speakers without cleft palate aged 13 to 45 years participated in this study. Two listeners judged the degree of nasality in speakers with cleft palate with or without cleft lip. Two distinct acoustic energies derived from the mouth and nose were recorded simultaneously while speakers were producing the speech tasks /pimip/, /pamap/, and /pumup/. Absolute and proportional measures related to nasalization duration were obtained.

RESULTS

Speakers with cleft palate with or without cleft lip exhibited more extensive acoustic nasalization in the time domain than did speakers without cleft palate with or without cleft lip. Speakers without cleft palate with or without cleft lip showed larger nasalization-duration ratios in the high vowel contexts than in the low vowel context. Speakers with cleft palate with or without cleft lip did not exhibit distinct differences in nasalization-duration ratios among the vowel contexts. The acoustic measurements reflecting temporal patterns of oral-nasal acoustic impedance were related to the perception of hypernasality.

CONCLUSIONS

These results suggest that the speakers with cleft palate with or without cleft lip showed longer duration of acoustic nasalization than speakers without cleft palate with or without cleft lip. Temporal characteristics of acoustic nasalization grew longer as the degree of perceived hypernasality increased. The positive correlation between temporal measures of acoustic nasalization and degree of perceived nasality suggests that temporal measures of nasalization would provide supplementary diagnostic information in relation to the degree of hypernasality.

Characteristics of Korean phonology: review, tutorial, and case studies of Korean children speaking English

A significant number of bilinguals in English-speaking countries speak Korean as their first language. One such country is the United States (U.S.). As the U.S. becomes increasingly diverse, providing more effective services for culturally and linguistically diverse children is a critical issue and growing challenge for speech-language pathologists. The U.S. Census Bureau reports that the number of Korean immigrants in the U.S. has steadily increased over the past decade. As a result, a greater number of children who speak Korean as a first or second language may need speech, language, and hearing services. This paper provides a review of the literature on (1) phonological characteristics of the Korean language and (2) speech sound acquisition and developmental patterns for phonological processes in Korean children. We illustrate how language knowledge of Korean might impact the learning of English based on case studies of three Korean children speaking English in the U.S. We describe considerations for more appropriate evaluation and treatment of speech sound disorders in Korean-English-speaking children.

LEARNING OUTCOMES

Readers will be able to: (1) understand phonological characteristics of the Korean language and speech sound acquisition and developmental patterns for phonological process in Korean children, (2) describe characteristics of English speech sound acquisition in successive bilingual English-Korean learners and interference patterns that result from the influence of two independent phonological and phonetic systems, and (3) describe considerations and clinical implications for the more appropriate evaluation and treatment of speech sound disorders in Korean-English speaking children.