Phonological development and disorder of Putonghua (modern standard Chinese)-speaking children
This thesis investigates the influence of universal tendencies and language-specific features on phonological development of Putonghua-speaking children in both normally developing and exceptional circumstances (i.e. children with speech disorder, with hearing impairment, and twins). It provides the first normative data on this population as well as cross-linguistic evidence on issues raised by research on English-speaking children. A cross-sectional study of 129 normally developing children aged 1 ;6-4;6 and a longitudinal study of four children between the age of 1;0 and 2;0 showed that Putonghua-speaking children completed the acquisition of the four elements of Putonghua syllables in the following order: tone first, then syllable-final consonant and vowel, and syllable-initial consonant last. The age and order of phoneme acquisition and the chronology of phonological processes were derived and subsequently employed as an assessment tool in the study of disordered phonology. It was found that the frequency of the phonemes across the world languages, the biological constraints or articulatory limitations of young children, the theoretical concept of universal 'markedness' or 'default features' and the current proposal of 'functional load' have a number of explanatory inadequacies in accounting for cross-linguistic similarities and differences in the rate and order of phoneme acquisition. Instead, some cross-linguistic variations in the rate and order of acquisition of vowels, consonants and prosodic features such as tone, are better accounted for by the concept of 'phonological saliency'. Components with higher phonological saliency would be acquired earlier than components with lower saliency. The effects of both universal tendencies and language-specific features were also evident in the phonological systems of children developing in atypical circumstances, as the studies of children with speech disorder, a child with hearing impairment and a set of twins showed. In addition, the analysis of the phonological systems of 33 Putonghua-speaking children with functional speech disorder provided further cross-linguistic support for a 'four subgroup categorisation system'. The follow-up study on the development and change that occurred to the phonological systems of seven Putonghua-speaking children with speech difficulties showed that children with different underlying deficits might follow different paths of development. Delayed phonological development may occur at any stage of children's phonological acquisition and spontaneously resolve later, while disordered phonological development may start at speech onset and be resistant to change, due to deficits in the speech processing chain. The analysis of the phonological systems of a set of Putonghua-speaking twins showed that the phonological systems of the co-twins were not identical, though both evidenced characteristics of delayed or disordered phonological development and shared some error patterns. They were able to comprehend both adult and their sibling's phonological forms, suggesting a dual phonological representation in their mental lexicon. The phonological development of a Putonghua-speaking child with severe prelingual hearing impairment between the age of 3;5 and 4;5 suggested that children with hearing impairment may have difficulties in generalising accurate information about the regularities of the target phonological system, as the result of early deprivation or degradation of auditory input and a cognitive deficit in processing phonological information. The thesis as a whole contributes to the theory concerning phonological development and disorder across languages and across different populations.