Is the movement deficit in syntactic SLI related to traces or to thematic role transfer?

Children with Syntactic Specific Language Impairment (S-SLI) have difficulties understanding object relative clauses, which have been ascribed to a deficit in syntactic movement. The current study explores the nature of the deficit in movement, and specifically whether it is related to a deficit in the construction of syntactic structure and traces, or whether the structure is constructed correctly but the transfer of thematic roles from the trace is impaired. This question was addressed using reading aloud and paraphrasing of object relatives that included noun-verb heterophonic homographs after the trace. Because the correct reading of homographs as noun or verb critically hinges on the identification of their syntactic position, readers who cannot construct traces are expected to read homographs incorporated after the trace incorrectly. The participants were 15 Hebrew-speaking children aged 9.3 to 14.6 with S-SLI and 50 typically developing children. The children with S-SLI read the homographs after the trace correctly but failed to interpret the object relatives, making thematic role errors. The results suggest that in S-SLI, at least for school-aged children, syntactic structure and traces are created, but the assignment of thematic roles from the trace to the moved element is impaired, leading to a deficit in the comprehension of movement-derived sentences.