On the production of restrictive pied-piping relative clauses in Italian: evidence from populations with typical and atypical language development

Restrictive relative clauses are among the most frequently studied structures in language development across different languages and different populations. While much literature is devoted to the acquisition and use of subject and object relatives introduced by that, pied-piping (prepositional and genitive) relatives have been less studied. This paper offers an overview of some recent studies in which these structures were investigated in Italian typically developing (TD) individuals and in individuals with learning difficulties (LD) using the same procedures, namely repetition and/or elicited production. Early studies found that pied-piping relatives are acquired not earlier than 10 years of age. Much subsequent research on Italian found that the rate of production of these structures increases with age increase, but it never reaches ceiling effects. Although percentages increase for both populations, the level of accuracy for individuals with LD is lower than for TD individuals. This is expected, since pied-piping relatives are typical of a formal, written register, to which people with LD have difficult access. However, low frequency in speech cannot be the only explanation for the low rate of production. Syntactic complexity, agreement phenomena, and number of arguments that receive thematic role explains the difficulties with these structures.