An explorative study of the error profile of children with DLD: Retention difficulties with phonemic item and order information during nonword repetition
Summary
It has been widely reported that children with developmental language disorder (DLD) are outperformed by their TD peers regarding their abilities to repeat nonwords. The poor nonword repetition of children with DLD has been suggested to reflect limitations in phonological short-term memory (pSTM), a memory system in which verbal material can temporarily be stored. However, it is unclear whether their problems with repeating nonwords are situated at the level of retaining items (i.e. phonological characteristics), order (i.e. the phonemes’ position), or both. The present paper aimed to address this question, to gain more insight in the kind of retention problems that children with DLD experience, which is relevant for clinical purposes. Additionally, insight in the error patterns is theoretically of interest, as it sheds light on the question whether children with DLD differ from their TD peers by a delay or a deviance. In total 39 Dutch children with TD and 39 Dutch children with DLD participated in a nonword repetition task (NWRT) at 72 and 95 months of age. The children were matched on age and nonverbal IQ. Their nonword repetitions were analysed in terms of accuracy, and error patterns. Results revealed that with increasing age the groups improved at the same pace, but at both ages the DLD group was outperformed by the TD group. Error patterns did not change with age. Although children with DLD made relatively more combined errors, the overall error profiles of the two groups were largely the same: Item errors were most frequent, followed by combined errors, which were in turn followed by order errors. These findings suggest that the retention problems of children with DLD are similar to the retention problems of their TD peers, but that the problems of the DLD group are more severe. Retention problems were mainly situated at the level of item information, and to a lesser extent at the level of order information.