Acquisition of exhaustivity in wh-questions: A semantic dimension of SLI?

This paper investigates how exhaustivity in single and multiple wh-questions is acquired in German-speaking children with SLI. Comparing semantic and pragmatic accounts of exhaustivity, obligatory exhaustivity of multiple wh-questions is argued to be problematic for pragmatic approaches. A unified semantic approach is suggested that relates exhaustivity to an inherent property of the question meaning. Two question-with-picture experiments explored the comprehension of four wh-question types (single wh-questions with and without the quantifying question particle alles, paired and conjoined wh-questions) in 5-year-old children. Twenty children with SLI, 20 typically developing (TD) children, and 20 adults participated in Experiment 1, and 17 TD children in Experiment 2. The results indicate that 5-year-old TD children have acquired exhaustivity in single and paired wh-questions. The children with SLI mastered wh-alles-questions, but not the other wh-question types. For single wh-questions, the most frequent errors were singleton answers, and for paired and conjoined wh-questions exhaustive lists of subjects or objects; plural responses were not found. Within individual children, single wh-questions were acquired before paired wh-questions. These findings suggest that a unified theory for both single and paired wh-questions is desirable, one which attributes exhaustivity to universally exhausting the question domain - a property that SLI children do not possess. These results add to recent research indicating that children with SLI may have deficits in semantics.