The movement deficit in SLI: Trace deletion or thematic role transfer impairment

Children with Specific Language Impairment have difficulties understanding relative
clauses, difficulties that have been ascribed to a deficit in phrasal movement. The current
study explores the nature of this deficit in movement, and specifically whether it is
related to a deficit in the construction of traces, or whether traces are constructed, and the
deficit is related to a failure to transfer thematic roles via chains. This question was
assessed using reading-aloud of noun-verb homographs that are incorporated in object
relative sentences, and their correct reading critically hinges on the correct processing of
the object relative sentence. We used a property of Hebrew orthography, the
underrepresentation of vowels, that makes the reading of homographs dependent on the
sentence. The rationale behind the study was that readers who cannot process or represent
traces of movement, are expected to fail in identifying the syntactic role of such
homographs when they are incorporated after the trace position in movement-derived
sentences, and therefore fail to read them. Nine school-age Hebrew-speaking children
with SLI, and nine participants without language impairment read aloud and paraphrased
such sentences. The children with SLI read the homographs after the trace correctly but
failed to interpret the object relative sentences. They interpreted well the sentences that
were not derived by movement. The study indicates that traces of movement are created
in SLI but the assignment of thematic roles via chains is impaired.