一、选题背景与意义（说明所选课题的历史背景、国内外研究现状和发展趋势）

Successful mastery of a language should reveal itself in both comprehension and production. They are closely linked in language development. Normative studies of language development usually suggest that auditory comprehension (reception) precedes productive speech. Thus, it is reasonable to ask whether the deliberate development of receptive language skills will facilitate acquisition of productive speech. Performance for Pediatric Speech Intelligibility (PSI) Format I and Format II sentences was significantly different in children between the ages of 3 and 6 years. Performance differences were related to chronological age (CA) and receptive language (RL) abilities. Typically developing (TD) children demonstrate age-related improvements in language processing. However, studies revealed that children with language impairment (LI) showed a significant delay in language development. But there was no difference between LI children and typically developing (TD) children in total language age, semantics, pragmatics and expressive language age. The only scale that showed difference between children with LI and TD children was the receptive language age and receptive age quotient. So it is important to take into consideration receptive language age when assessing the development of syntax among 3-6 years old children.

In the context of production there are a number of possibilities for arriving at a comprehensible output. As we can see, correct comprehension can coexist with various strategies in production that reflect the maturation of processes involving several syntactic variables. Existing work on the acquisition of syntax has been concerned mainly with the syntax development in children. Structural priming paradigms have shaped theories of syntactic development. Priming studies with children have focused on what priming can tell us about children’s syntactic representations. Thus, it is reasonable to ask how structural priming changes across development. Two of the most robust findings in the adult literature are the abstract structural priming effect and the lexical boost. However, the data from typically developing children are less clear-cut. So it is important to take into consideration the abstract structural priming effect and the lexical boost when assessing the development of syntax among 3-6 years old children.

1. Literature review

1.1 Receptive sensitivity

Normative studies of language development usually suggest that auditory comprehension (reception) precedes productive speech- i.e., a child learns first to respond to speech and later to express himself in speech. This observation is supported by several research studies (McCarthy, 1954; Fraser, Bellugi, and Brown, 1963) and frequently appears as a statement of theory (Myklebust, 1957; Chomsky, 1967; Lenneberg, 1962). Thus, it is reasonable to ask whether the deliberate development of receptive language skills will facilitate acquisition of productive speech (Donald M. Baer, 1973).

1.1.1 Receptive language age

Typically developing (TD) children demonstrate age-related improvements in language processing (i.e. they become faster processors). Performance for Pediatric Speech Intelligibility (PSI) Format I and Format II sentences was significantly different in children between the ages of 3 and 6 years. Performance differences were related to chronological age (CA) and receptive language (RL) ability. (Susan Jerger et al., 1981) Studies indicated that there was some relationship between age and rate of learning. The older children scored higher on the syntax subtests. These results suggest that there is a difference in the rate of learning of syntax based upon differences in age (Ann Fathman, 1975). For TD children, their reaction time (RT) should be unaffected by rate manipulation, as their language-processing system is sufficiently robust to handle such a simple input manipulation. They showed the response pattern: the fastest RT for fast-rate sentences and the slowest RT for slow-rate sentences. But age had a significant effect. Regardless of language status, older children produced faster RT than younger children. Thus, the language proficiency of children improves with age. The results of logistic regressive analysis indicate that the speech production measured depends decisively on age at implantation, age at time of test, speech production before implantation, and additional handicaps (Bernhard Richter et al., 2002). Results revealed that children with Attention deficit-hyperactivity disorder (ADHD) showed a significant delay in language development. But there was no difference between ADHD children and TD children in total language age, semantics, pragmatics and expressive language age. The only scale that showed difference between children with ADHD and controls was the receptive language age and receptive age quotient. (Safaa Refaat El Sady et al., 2013) Therefore, we should take receptive language age into consideration when assessing the development of syntax among 3-6 years old children.