Levels of Complexity of OO and SO Type Relative Clauses in Preschool Persian Speaking Children

In Recent decades, processing RCs and studying their complexity in different languages has had an important role in linguistic and psycholinguistic research. This study is to compare the complexity of two types of Persian RCs (OO and SO). This complexity is assessed on the psychological criterion of preschool children’s understanding of sentences in which these types of RCs are used. Ninety six (96) Persian native children, in three different ranges of ages ( 3-4, 4-5, and 5-6 ) took part in this study. They were presented by the fore-mentioned sentences in two different forms of declarative and interrogative, and their understanding of these sentences was tested. The result showed that SO type RCs, both in declarative and interrogative forms, were clearly more complex than OO type RCs.