Vowel Nasality And Articulation Accuracy In Mandarin Produced By Children With Cleft Palate

The cleft palate(CP)is a congenital malformation in the oral and maxillofacial region.Hypernasality is one of the most salient features in cleft palate speech,especially in the production of vowels.Previous studies on CP speech varied in stimulus designs and measurements of vowel nasality,however,there is a lack of research which has systematic and comprehensive measurements and wide-coverage stimuli with different onsets and rimes in legal phonotactics in Mandarin.This study mainly investigates the vowel nasality and articulation accuracy in Mandarin produced by children with CP,using three kinds of assessments: perceptual assessment,articulatory measurement of nasality,and acoustic measurement of nasality.The first assessment examines the articulation accuracy of the onset and the rime in Mandarin,and the last two measurements correspond to the vowel nasality.Twenty CP children and twenty typically developing(TD)children(4-10 years old)were recruited in this study to produce 157 tokens,including 10 monophthongs and 147 high-frequency disyllabic words in Mandarin.Target syllables refer to 10 monophthongs and the first syllable in the disyllabic words which involve the combination of 10 rimes(sorted to monophthongs,alveolar nasals,and velar nasals)and 21 onsets(sorted to zero,nasal,lateral,and obstruent onsets)in Mandarin.Four research questions were addressed:(1)Are there any differences between children with cleft palate and typically developing children in vowel nasality and articulation accuracy?(2)Do the onset and rime affect the vowel nasality in CP children’s speech production? If so,how do these two factors affect the vowel nasality?(3)Do the onset and rime affect the articulation accuracy of CP children’s speech? If so,how do these two factors affect the articulation accuracy?(4)Are there any relationships between results of perceptual assessment,articulatory measurement,and acoustic measurement?Three kinds of assessments were conducted separately.Vowel nasality in the articulatory measurement was statistically analyzed through mixed-effects linear regression model.Results showed:(1)CP children produced significantly higher vowel nasality in the monophthongs with non-nasal onsets compared to TD children.There was no significant group difference in the production of nasal rimes.(2)Vowel nasality hierarchies were discovered for both groups:(1)monophthongs [i] > [u] > [?] > [a];(2)alveolar nasals [in] > [?n] > [an];(3)velar nasals [i?] > [??] > [ɑ?].(3)Vowel nasality in the nasal onsets was the highest among all the onsets and significantly differed from other onsets.This phenomenon was more salient in the TD group than in the CP group.The acoustic assessment of nasality was also analyzed through mixed-effects linear regression model.Results showed no group difference in the rimes of [an],[in],[i?],and [u].The group difference was more prominent in the onsets of zero and obstruent than in other onsets.Mixed-effects logistic regression model was conducted to analyze the data in the perceptual assessment of the onsets and the rimes produced by CP and TD children.Results indicated that TD children showed significantly higher accuracy than CP children for the perceptual identification of the onsets,and both groups demonstrated the highest accuracy in nasal onsets,the median in obstruents,and the lowest in laterals.For the perceptual identification of the rimes,CP children produced monophthongs as well as the TD group.Both groups displayed high accuracy in [an] and [ɑ?],and low accuracy in [?n] and [??] in the nasal rimes and indicated the lowest accuracy when producing rimes with nasal onsets.The present study investigates the vowel nasality and articulation accuracy in the cleft palate speech in Mandarin,using three kinds of assessments which emphasize on different aspects of CP speech.It is better to integrate them to present a more comprehensive picture.In general,CP children demonstrated higher vowel nasality and lower articulation accuracy than TD children.Vowel nasality hierarchies are noticeable for both groups.Lower accuracy and higher vowel nasality are discovered in the rimes with nasal onsets than other onsets.This study attempts to provide theoretical support and database for the diagnosis,assessment,and therapy of cleft palate speech in clinics,which indicates certain social practical significance.