According to the definition of the American Speech-Language-Hearing Association, in children, speech sound disorders (SSDs) are defined as speech errors that persistent even after a certain age. Studies have shown that children with SSDs may have problems with phonological perception and phonological awareness in the preschool stage. Some studies have suggested that when treating phonological abnormalities in children, training for speech perception and phonological awareness may also improve treatment effectiveness. However, at present, studies examining the relationships between speech perception, phonological awareness, and speech production of children with SSDs are lacking. To develop an effective intervention plan for children with SSDs, the relationship between speech output and speech processing-related variables should be determined. This study systematically examined the correlations between the speech production of children with SSDs and their levels of speech perception and phonological awareness to provide empirical evidence for improving clinical intervention design. By using speech processing models, this study inferred the possible reciprocal relationships between speech perception, phonological awareness, and speech production. Children develop speech perception abilities (such as basic abilities to discriminate and identify speech sounds) in the early stages of development. This basic speech perception ability affects their abilities of speech production and of phonological awareness (e.g., building phonological representations and manipulations). The development of phonological awareness would improve the fineness of speech perception abilities, which in turn affects the capacity of speech production. Moreover, the perceptual and motor feedback provided based on the speech production ability in preschool children may also promote the development of speech perception and phonological awareness in these children. Although the reciprocal relationships between speech perception, phonological awareness, and speech production in children with typical development or children with SSDs have not been consistently demonstrated in the literature, speech perception, phonological awareness, and speech production are hypothesized to have mutual influence in children with SSDs during preschool ages. This study examined the relationships between speech perception, phonological awareness, and speech production in preschool children with SSDs. Participants were 46 Mandarin-speaking children aged 5 years (39 boys and 7 girls) with SSDs and without any other sensory or developmental disabilities, such as intellectual disability, cerebral palsy, or hearing impairment. Their nonverbal IQ was higher than 80 on the Test of Nonverbal Intelligence-Fourth Edition (TONI-4). Their language comprehension was also more than −1.5 standard deviation on the scandalized language test. Several self-made computerized and standardized tests were used to measure their speech perception, phonological awareness, and speech production abilities. For speech perception, pure tone discrimination, speech discrimination, and categorical perception assessments were conducted. For phonological awareness, assessments of rhyme judgment, initial sound judgment, tone judgment, and syllable deletion were designed. For speech production assessment, we used the Articulatory and Phonological Test for Mandarin-Speaking Children to assess individual children’s percentage of correct word production. In addition, the speech samples elicited from the conversation, comic strip cards, and storybooks were collected and analyzed to index the percentage of correct consonants for individual children. Correlation and multiple regression analyses (including path analysis) were used to examine the relationships among these three speech-related abilities as well as the ability of speech perception and phonological awareness to predict speech production in Mandarin-speaking children with SSDs. After controlling for age, language comprehension, and nonverbal IQ, correlations were observed between the speech perception, phonological awareness, and speech production of children with SSDs. Most measures of speech perception and phonological awareness were significantly correlated; however, partial correlations were found between the measures of speech perception and speech production. For example, the identification slope of consonants and tones was significantly correlated with the speech production ability, but pure tone identification was not correlated with speech production. Speech production was only correlated with syllable deletion, but not with other indexes of phonological awareness (i.e., rhyme judgment, initial sound judgment, and tone judgment). Furthermore, the results of multiple regression analysis showed that the identification slope of consonants, tone perception, and syllable deletion had explanatory power for speech production. That is, the speech perception and phonological awareness abilities at the syllable level could predict the variance of speech production. Among the predictive factors, the identification slope of speech was the most powerful predictor of speech production. In path analysis with speech production as the dependent variable, the categorical perception of consonants and tone had direct predictive power for speech production. This study revealed that after controlling for age, language comprehension, and nonverbal IQ, the speech perception sensitivities of consonants and tones (especially the phonetic identification of categorical perception) and phonological awareness (i.e., syllable deletion) of children with SSDs were significantly correlated with their speech production at 5 years of age. Among them, categorical speech identification had direct predictive power for speech production, showing that this ability has important influence on speech production, and this result indicates that children with SSDs may have inferior abilities of speech perception and phonological awareness. This study analyzed the phonological processing ability of children with SSDs, and the results are similar to the previous hypothesis for the normal development of children’s phonological processing; that is, speech perception ability affects speech production ability, and phonological awareness ability affects speech perception ability. The improved phonological awareness ability may increase the fineness of speech perception, which in turn affects the speech production ability. The perception or articulation feedback provided during speech production also promotes the further development of speech perception and phonological awareness. Overall, a close interaction exists between the three speech-related abilities as described above. The phonological processing capabilities covered in this research include speech perception and phonological awareness; however, phonological processing should include other aspects (such as phonological working memory). Therefore, future studies should explore other phonological processing abilities of children with SSDs to gain a comprehensive understanding of the phonological causes of SSDs. In addition, currently, two major approaches of intervention exist for children with SSDs, one based on motor skill training and the other based on language processing training. The articulation-based training model focuses on motor skill training for speech production, and this training mainly involves teaching the correct articulatory movements of individual speech sounds at the speech production level. The language processing–based model emphasizes the buildup of correct phonological representation of the complex phonological system for children with SSDs to correct inaccurate speech representations and speech errors. According to the results of this study, training involving both “listening” and “speaking” is important and should be conducted as an early speech intervention for children with SSDs. In terms of listening training, establishing phonetic discrimination (i.e., distinguishing the same or different speech sounds), identification (i.e., defining the specific speech sound category), and phonological awareness (i.e., detecting specific phonemes) may facilitate speech production in preschool children with SSDs. The establishment of correct phonological representations for children may facilitate precise speech production. In terms of speaking training, children should be supported to observe the position and movements of the speech organs during articulation training. The feedback of correct speech production movements can also facilitate children’s speech perception abilities. Overall, the developments of speech perception, phonological awareness, and speech production are intercorrelated. Speech perception and phonological awareness training should be combined when implementing speech interventions for children with SSDs to improve their speech sound production.
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