Phonetic and phonological characteristics of Mandarin-speaking children with repaired cleft palate
Children with cleft palate, with or without associated cleft lip (CP±L), often demonstrate speech problems even after surgery for palatal repair. Speech characteristics in children with CP±L have been well studied for English-speaking children but under-investigated for Mandarin-speaking children. As the most spoken language in the world, Mandarin shows language-specific features that are different from English. To understand the speech characteristics of Mandarin-speaking children with CP±L, this dissertation investigated phonetic and phonological characteristics in children with CP±L and in typically-developing children using an existing database from a Chinese hospital. In total, speech samples of 46 Mandarin-speaking children with CP±L from age 5 to 8 years and 37 age-matched typically-developing children were included in this study. The following types of phonetic and phonological characteristics were analyzed: consonant inventory, speech accuracy, phonological processes, and cleft palate speech characteristics. The consonant inventory was analyzed based on the total number of consonants and the phonetic features of these consonants. Speech accuracy was examined using the percentage of correct consonants (PCC), percentage of correct places (PCP), and percentage of correct manners (PCM), and then specifically analyzed by the percent correct within each category of consonant place and manner. Phonological processes were confirmed by the percentage of occurrences out of the possible opportunities in phonetic contexts. Cleft palate speech characteristics were measured by perceptual ratings on speech samples using a modified version of the Cleft Audit Protocol for Speech-Augmented (CAPS-A). The speech outcomes in children with CP±L were compared to those in typically-developing children. Speech outcomes were also compared among four age groups (i.e., 5, 6, 7, and 8 years), and then among three surgical timing groups (i.e., before 1 year of age, between 1 and 3 years of age, and after 3 years of age). Results showed that Mandarin-speaking children with CP±L demonstrated smaller consonant inventories, lower speech accuracy, and more frequent occurrences of phonological processes compared to typically-developing children without clefts. No significant difference in any speech outcome was found among the four age groups. Children with CP±L who had early surgery before 1 year of age demonstrated fewer occurrences of nasal assimilation than those who had surgery after age 3 years. Children who had surgery between ages 1and 3 years were considered less hypernasal than those who had surgery after age 3 years. These findings add information regarding speech characteristics in Mandarin-speaking children with CP±L from ages 5 to 8 years. The insights of language-specific features gained from this study may be of assistance to improve speech services for Mandarin-speaking children with CP±L. Future studies with larger sample sizes and longitudinal study designs to investigate the window of speech development in Mandarin-speaking children with CP±L are warranted. Future research could also be conducted to develop and validate a modified version of the CAPS-A for Mandarin-speaking children with CP±L.