Abstract
This article discusses tests using the Developmental Sentence Score for Japanese (DSSJ), a new language measure of grammar development. Twenty language samples from three children with mental retardation (MR); three children with pervasive developmental disorders (PDD) with a development age between 2; 6 and 4; 3, and five typically developing children between 2; 0 and 3; 6. DSSJ scores were compared to the (developmental) age, as well as to the Mean Length of Utterance in Morphemes (MLUm). The correlations between DSSJ and MLUm were highly significant for both groups, while the correlations between the two measures and (developmental) age proved significant only for the typically developing children. PDD and MR children did not differ in terms of MLUm and DSSJ results. The typically developing children, however, showed a greater diversity after DSSJ 300, which points to the necessity of an extension of DSSJ items for the higher age range. The overall results suggest that DSSJ is a valuable measure of language development. The somewhat weaker correlation between the linguistic measures and developmental age shows that language development is not fully congruent with mental development. Developmental age alone then is not a sufficient predictor in the case of non-typical language development.
