The Acquisition of Object Clitics in Children with a Phonetic-Phonological Disorder: evidence from comprehension and production

Failure in the production of third person singular direct object clitics (3DO) is one of the main clinical markers of Developmental Language Disorders (DLD) in Italian. This study investigates the origins of this difficulty, examining whether it stems from grammatical limitations or prosodic deficiencies. We categorized children into two groups: those with DLD confined to the phonetic-phonological domain (DLD-P) and those with additional morphosyntactic deficits (DLD-M). Both groups were compared to typically developing (TD) children. Children were tested in a clitic elicitation task and in a clitic comprehension task. Surprisingly, DLD-P children exhibited no significant differences from TD children in either the elicitation or comprehension of 3DO clitics. Conversely, DLD-M children struggled notably, displaying marked disparities in both production and comprehension of 3DO clitics compared to both DLD-P and TD children. No difference was found between children with TD and children with DLD in the comprehension of reflexive pronouns. On the one hand, these results suggest that the acquisition of 3DO clitics cannot be considered purely a phonological-prosodic phenomenon, because if that were the case, we would expect children with selective phonetic/phonological impairment to underperform in clitic comprehension. On the other hand, these results emphasize the necessity of defining distinct subtypes within DLD and of identifying specific clinical markers for each subtype. By understanding the nuanced differences between these subtypes, we can better tailor interventions and support strategies for children with DLD, thereby enhancing their language development and overall quality of life.