The Modularity of Morphosyntax: Mentally Retarded Children’s Production of Conjugated Predicates in Korean

In this paper, we investigate whether mentally retarded (=MR) Korean children’s production of conjugated predicates follows the same generalization that has been reported for normal children’s language performance. For this, we elicited narratives from 15 MR children, and analyzed their production of conjugated predicates. We cross-classified the conjugation patterns in terms of four categorical variables: morphological class, (morpho-)syntactic conjugation, semantic class, and age. Results from the log-linear regression analysis show that MR children’s use of predicate conjugation is constrained by the same generalization that determines the distribution of normal children’s conjugation patterns. That is, both MR and normal children’s production of conjugated predicates is nicely predicted by the interaction between the morphological and semantic classes of each predicate, and by the main effect of conjugation type. The overall finding supports the modularity view of language in terms of morphosyntax; i.e. the language capacity is dissociated from the general cognition.