The child heard a coordinated sentence and wondered: On children's difficulty in understanding coordination and relative clauses with crossing dependencies

Children are known to have problems in understanding Wh-movement constructions in which the object moves across an overt subject (as is the case in object relatives, Wh-object questions, and topicalization). To test whether crossing dependencies are also problematic when no Wh-movement is involved and whether dependencies in which the subject crosses an object are also difficult, we test a construction that has not been studied before, a coordination sentence like The girl kissed the boy and went to the beach. This structure includes a dependency – between the empty subject of went to the beach and the girl. This dependency crosses the object the boy. We tested the comprehension of this construction in comparison with coordination that does not involve a dependency, and with coordination that includes a dependency without intervention. We also compared it with relative clauses with and without intervention, object relatives and subject relatives, respectively. We ran five experiments to assess the comprehension of these structures and the correlation between them. Experiments 1 and 2 tested sentence-picture matching in 49 3;4 to 5;5 year old Hebrew- and European-Portuguese-speaking children; Experiments 3 and 4 used comprehension questions in 41 3;6 to 5;6 year old Hebrew- and European-Portuguese-speaking children. Experiment 5 tested the correlations between the structures in 69 school-age children. The main findings were that children performed poorly on the comprehension of sentences containing crossing dependency coordination, in all 5 experiments, and in both languages. Their difficulty in the crossing dependency coordination was similar to their difficulty with object relatives, and their performance on crossing dependency coordination correlated with that of object relatives. Their performance on coordination without dependency, coordination with a dependency but without crossing, and subject relatives was good. We conclude that crossing dependencies, not only in Wh-movement dependencies, underlie the difficulty in young children's sentence comprehension.