Purpose. This study investigated the morpho-syntactic abilities of children who show deficits in reading comprehension in spite of adequate word reading abilities. These children are often referred to in the literature as “poor comprehenders,” and their reading comprehension problems are believed to stem from oral language deficits. In fact, many studies have documented poor comprehenders’ deficits in semantics, syntax, and higher level language skills. Because most poor comprehenders also display normal nonverbal cognitive skills, they share much in common with children with specific language impairment (SLI), and studies have documented substantial overlap between the two classifications. This study sought to determine whether poor comprehenders display the same morpho-syntactic deficits that are characteristic of children with SLI.

Method. Sixteen poor comprehenders and 24 controls participated in this study. All participants were in fourth grade and demonstrated good word reading and nonverbal cognitive abilities. They completed a battery of standardized language assessments and three experimental morpho-syntax tasks that examined knowledge of finiteness marking rules. The first two sets of analyses were conducted to determine if poor comprehenders showed morpho-syntactic weakness relative to controls and if their pattern of performance was characteristic of expectations for children with SLI. Then the poor comprehender group was subdivided into those who met criteria for SLI (PC-SLI) and those who did not (PC-Only). The third set of analyses looked for differences in morpho-syntactic performance between poor comprehenders with SLI and poor comprehenders without SLI.

Results. The poor comprehender group achieved significantly lower scores than the control group on all non-phonological standardized language assessments, but the two groups performed equivalently on the phonological processing measure. The poor comprehender group also showed significantly weaker performance than controls across the three morpho-syntax tasks, and their pattern of performance indicated weakness with obligatory finiteness marking, regularization of irregular past tense, and subject-verb agreement. The first two weaknesses are characteristic of children with SLI. Although subject-verb agreement is not believed to be an issue for children with SLI, a small number of studies of older children with SLI have reported difficulty with this area. There was no distinguishable pattern of differences in morpho-syntactic performance between the PC-SLI and PC-Only groups. These results have implications for the early identification of later reading comprehension difficulties in children with good phonological skills.