Which questions are most difficult to understand?

This study explored Wh question comprehension in Hebrew-speaking children with syntactic SLI, comparing which and who questions and subject and object questions. The participants were 28 Hebrew-speaking children with SySLI aged 9;3-12;0, and the control group included 25 typically-developing children aged 9;1-10;0. The study used three picture selection tasks. The results indicated that the children with syntactic SLI had a severe deficit in the comprehension of which object questions. Most of them performed randomly on these questions, and each of them performed significantly poorer than the control group. They understood subject questions better than object questions, and who questions better than which questions. These results join a growing body of evidence suggesting a deficit in sentences derived by Wh movement in syntactic SLI. We suggest that this deficit relates to the assignment of a thematic role to an element which moved across another argument of the same type. The second part of the study explored subtypes of SLI. We compared the comprehension of Wh questions in three groups of children with SLI: syntactic SLI (S-SLI or SySLI), lexical SLI (LeSLI), and pragmatic SLI (PraSLI). The results showed that whereas children with SySLI have a significant deficit in the comprehension of which object questions, children with LeSLI and PraSLI understand Wh questions without difficulty.