SV sentences with unaccusative verbs like "The leaf fell" involve movement from object to subject position. This line of studies tested whether young children can produce this movement and whether they represent SV sentences with unaccusatives as derived by movement. In Hebrew, unaccusatives appear in both SV and VS orders. This optionality allows for the testing of the acquisition of object-to-subject movement. If it is not yet acquired, children are expected to produce unaccusatives in their base-generated VS order, and refrain from the SV order, or, if they assign unaccusatives an analysis of unergatives, they are expected to produce unaccusatives only in SV order, as they do with unergatives, and without possessive datives. Seven experiments assessed the production of unaccusatives and unergatives in 136 1;9-4;0-year-old Hebrew speakers, using tasks of sentence repetition, story retelling, and analysis of spontaneous speech. The results indicated that children younger than 2 years already produce SV sentences with unaccusatives. They distinguish between unaccusatives and unergatives, as they use both VS and SV orders for unaccusatives, but only SV for unergatives. They use possessive datives with unaccusatives, indicating that they analyze the argument of the unaccusative as an internal argument. Thus, children younger than 2 years can already move the argument of unaccusatives from object to subject position, namely, they can construct A-chains. (Contains 3 tables, 4 figures and 14 footnotes. The list of all sentences in Experiments 2-7 is appended.) [Research for this article was supported by the Israel Science Foundation.]