• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.161-169
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• 2014

This study investigated changes in the prelinguistic vocal production of typically developing infants aged 5-20 months based on Stark Assessment of Early Vocal Development-Revised (SAEVD-R). Fifty-eight typically developing infants participated in the study, and they were divided into four age groups, 5-8 months, 9-12 months, 13-16 months, and 17-20 months of age. Vocalization samples were collected from infants' play activities and were classified into 5 levels and 23 types using SAEVD-R. The results revealed that the four age groups showed significant differences in production proportion of vocalization levels. Level 1, 2, 4, and 5 vocalizations exhibited significantly different across the four age groups. Level 3 was predominantly produced across every age group. Therefore, the vocalization level was not significantly different across the four age groups. Especially, vowels in Level 3 vocalization predominantly produced across all ages during a long period. Also, significant increases in the proportion of Levels 4 and 5 occurred after 9 months, which suggested that the production of cannonical syllables is a key indicator of advancement in prelinguistic vocal development. The results have clinical implication in early identification and speech-language intervention for young children with speech delays or at risk.

• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.63-73
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• 2015

This study investigated longitudinally early vocalization and phonological developments of typically developing children. Ten typically developing children participated in the study from 9 months to 18 months of age. Spontaneous utterance samples were collected at 9, 12, 15, 18 months of age and phonetically transcribed and analyzed. Utterance samples were classified into 5 levels using Stark Assessment of Early Vocal Development-Revised(SAEVD-R). The data analysis focused on 4 and 5 levels of vocalizations classified by SAEVD-R and word productions. The percentage of each vocalization level, vocalization length, syllable structures, and consonant inventory were obtained. The results showed that the percentages of level 4 and 5 vocalizations and word significantly increased with age and the production of syllable structures containing consonants significantly increased around 12 and 15 months of age. On average, the children produced 4 types of syllable structure and 5.4 consonants at 9 months and they produced 5 types of syllable structure and 9.8 consonants at 18 months. The phonological development patterns in this study were consistent with those analyzed from children's meaningful utterances in previous studies. The results support the perspective on the continuity between babbling and early speech. This study has clinical implications in early identification and speech-language intervention for young children with speech delays or at risk.