Stages rather than ages in the acquisition of movement structures: Data from sentence repetition and 27696 spontaneous clauses

This study explored the order of acquisition of various types of syntactic-movement and embedding structures in Hebrew, using a sentence-repetition task, in which 60 children aged 2;2-3;10 repeated 80 sentences (with a total of 4800 sentences), and an analysis of the spontaneous speech of 61 children aged 1;6-6;1 (27,696 clauses: a group analysis of 56 children each with one sample, and a longitudinal analysis of 5 children). The sentence repetition task revealed a set order of acquisition of the various types of syntactic movement: A-movement is acquired first, then A-bar-movement, and finally movement of the verb to C. The analysis of spontaneous speech revealed the same order, and added several structures: A-movement of the object of unaccusative verbs to subject position appears first, together with simple SV sentences; then, wh-questions appear; then relative clauses and topicalization appear together with embedding of finite clauses, and lastly, V-to-C movement. Previous studies have shown that Hebrew speakers under age six have difficulty comprehending and producing sentences with A-bar-movement in which a lexically-restricted object crosses over a lexically-restricted subject. And indeed, whereas children produced A-bar structures very early (in the group samples, wh-questions appeared from age 1;6, relative-clauses and topicalization from age 2;6), until age 5;8 these structures never included a lexical DP crossing over another lexical DP. Both tasks indicated that the order of structure acquisition is fixed, creating Guttman scales between structures, but different children acquire the same structure at very different ages. It seems that whereas the syntactic path and the stages of structure acquisition along it are constant between children, each child walks this path in their own pace.