The Issue Of Fine-tuning Of Linguistic Complexity In Child Directed Speech

The purpose of the present study is to find out whether the children's main language input (usually the mothers) modifies the linguistic complexity when talking to the children over time in adapting to the children's early language development.This paper is composed of five chapters, focusing on the issue of fine-tuning in CDS (Child Directed Speech) and its correlation with the children's early language development.Chapter 1 is the introduction, which introduces two significant theories in the field of language acquisition and the divergence between them. One is the nativist account of language acquisition put forward by Chomsky; the other is the input-based account of language acquisition put forward by Snow & Ferguson, etc.Chapter 2 presents a detailed review of the previous studies on the adjustment of CDS and its correlation with children's early language development, in the order of phonetic studies, lexical studies and syntactic studies. In the present study, we employ 13 linguistic variables to examine the issue of fine-tuning, analyzing the longitudinal development of a Changsha infant and the maternal speech directed to him. In a parallel comparative study, we apply the same linguistic variables to the child directed speech of an English-speaking mother and to the child's early language development.Chapter 3 is the core part of the thesis, which studies a Mandarin-speaking mother's monthly conversations with her child LSY (male), with age ranging from 00; 09; 16 to 02; 03; 06. Besides, three conversations between adults (Adult Directed Speech; ADS) are also analyzed for the purpose of comparing the difference of CDS and ADS. Altogether, 4981 utterances from the mother's monthly input to LSY, 628 utterances from the ADS and 2116 utterances from LSY's early language production are included for the quantitative analysis.Chapter 4 contains the comparative study of the CDS and its correlation with child's early language development. The English mother-child conversations consist of 10 transcripts from Brown Corpus. The child is EVE (female), age ranging from 01; 06; 00 to 02; 03; 12. Altogether 4478 utterances from the English-speaking mother's monthly input to EVE and 3105 utterances from EVE's early language production are included for the quantitative analysis.The conclusions of the present study are manifested in the following four results. Firstly, CDS in the Mandarin-speaking mother differs from ADS since 10 out of the 13 linguistic variables show obvious difference between them. Secondly, neither the Mandarin-speaking mother nor the English-speaking mother fine-tunes their linguistic complexity with children'sage. Thirdly, the language of both children indicate radical change monthly whereas the language of both mothers only show slight variation, which suggests that the children themselves make great contribution to the language acquisition. Finally, there are similarities and differences between the two mother-child dyads situated in different linguistic and cultural environments.The above results demonstrate that children are not exposed to a finely-tuned language environment and they themselves play the most important role in the language acquisition. However, language input plays some role in the lexical acquisition of young children, namely in the acquisition of personal pronouns and verbs.