Management of sentence production demands.

This study examined the effects of variations in language complexity on young children's phonological accuracy and consistency of target words. A more general intent was to understand better the way in which developmental level and children's tolerance of speech variability influenced the management of processing demands. Seven children aged 22-34 months were seen six times over a 4-month period. During these sessions, children were presented with an elicited imitation task consisting of 18 stimulus words, each of which occurred in eight sentences of varying language complexity. Younger children in Language Stage III were found to be more influenced by changes in language complexity than older children in Language Stages IV and V. Within-stage differences were also found. Moreover, in contrast to previous research, children showed as many improvements in phonological accuracy with increases in language complexity as they did decreases in phonological accuracy. It was suggested that between-stage differences were primarily caused by differences in developing speech, language, and cognitive abilities, whereas within-stage differences were primarily caused by differences in the extent to which children tolerated variability in their speech. Based on this contention, some speculations were offered concerning the way in which normal and disordered children manage processing demands.