Children aged 2;0 to 4;4, including native speakers of English, Italian, Serbo-Croatian, and Turkish, were asked to demonstrate causative statements by acting them out with toy animals and dolls. The major analysis focused on the total number of correct acting-out responses and the way this score related to several variables. Performance improved with age within the range surveyed, but the rate of growth was not the same from one age period to the next. Children learning the two inflectional languages performed better than did children learning the two word-order languages. The superior performance of the Turkish-speaking children appeared to be related to the fact that Turkish inserts a particle in the verb to carry out this function, while the other languages express the causative with a periphrastic construction. The similarities and differences in performance growth curves also point to particular aspects of language development in the four languages. For instance, the Serbo-Croatian curve appears indicative of the children's difficulty in attending to both word order and inflectional cues. Continued errors at later ages are evident in both Italian and English, but the linguistic cause in each case is distinctive. In summary, the results suggest that sentence processing is aided by surface markings which identify the roles of particular words. (JB)