Mandarin-Speaking SLI And HFA Children's Acquisition Of Object Topicalization:An Experimental Study

Two experiments were carried out to explore Mandarin-speaking SLI and HFA children's acquisition of object topicalization(with OSV order): a production experiment,using a syntactic priming method,and a comprehension experiment,in the form of a sentence-picture matching task.Three groups of participants were recruited: 21 SLI children(identified through a battery of language tests and a nonverbal IQ test),32 HFA children(diagnosed by pediatricians or psychiatrists)and 28 age-matched Typically-Developing(TDA)children.The results revealed that the HFA children bore resemblance to the SLI children in that both groups performed significantly worse than their TDA counterparts in both the production experiment and the comprehension experiment.Conversely,differences were also witnessed between these two experiment groups in respect of their error patterns.First,in subject-object reversible context,the children with SLI produced significantly more SVO-type non-target responses than the HFA children,but produced notably fewer ‘AGENT-PATIENT reversed' Topic sentences.Second,the children with HFA produced significantly more ‘AGENT-PATIENT reversed' Topic-type error than the children with SLI did in the production experiment.In addition,they even produced such errors in subject-object irreversible context,which was not the case with the SLI group.What is more,a significant drop was seen in their production of the SVO-type non-target response in subject-object reversible context as compared with when the subject and the object of the base sentence are irreversible,resulting in an increase of other types of non-target response,especially the ‘AGENTPATIENT reversed' Topic-type error and the syntactically scrambled and semantically incorrect subtype.The poorer performance of the children with SLI and those with HFA as compared to their TDA counterparts is in line with the prediction of the Relativized Minimality principle(Rizzi 1990,2004).It is suggested that both of the two groups of children experience difficulties in acquiring object topicalization.As for the SLI children,we propose that the reason for their persistence in producing SVO sentences and their reluctance in producing sentences with movements is that they are sensitive to the syntactic complexity,which is accounted for by Derivational Complexity Hypothesis(Jakubowicz 2004,2005),further reflecting SLI children's special difficulties in acquiring structures involving syntactic movements.Since the HFA children produced significantly more topicalized sentences(though a few of them have wrongly reversed the AGENT and PATIENT theta roles)and significantly less SVO sentences in subjectobject reversible context than the SLI children,we propose that their difficulties in acquiring object topicalization originate from their difficulties in forming chain connections between the moved elements and the traces and in assigning thematic roles accordingly.