Acquisition of

Comprehension of reversible active and passive sentences was studied with 48 Japanese children between the ages of two and six. Four types of sentences were constructed using passive and active structures and two word orders: subject-object-verb CUM and ohject-subject-verb (OSV). The basic order of elements in a simple sentence in Japanese is SOY; but the order of the subject and the object can be interchanged to yield OSY. This reversal is possible because Japanese has postposed particles that mark grammatical role. To test comprehension with the four types of sentences, the children were required to act out the sentences using toy animals. In a production task, which immediately followed the comprehension task, subjects described what they saw on a slide viewer. Results suggest that children between the ages of three years, three months, and four years, two months, require a certai