Discuss - Girls have higher overregularization rates than boys.

This study was based on all extant large corpora of English-speakers available in CHILDES at the time. Since then, Kidd and colleagues (Kidd & Lum, 2008; Kidd & Kirjavainen, in press) have failed to find the same results using elicited production. However, overregularization in elicited production tends to differ from spontaneous production in many ways (e.g., it happens at a much higher rate). So it would be very useful to know if this is a failure of replication or a failure of *extension*. These results were some of the most compelling evidence that both productive and semi-productive processes are involved in over-regularization, so the reliability of the effect is important.