Inflection in Williams Syndrome

This study presents experimental results from elicited production and judgment tasks examining perfective past-tense forms of Greek in seven individuals with Williams Syndrome (WS) in comparison to three age groups of typically-developing children. We found that the WS group relied more on the regular (‘sigmatic’) past tense and less on the irregular (‘non-sigmatic’) one than typically-developing children. While for the sigmatic past tense, individuals with WS achieved the same or even higher scores as the controls, they had lower scores on several measures involving non-sigmatic forms and produced more overgeneralizations of sigmatic forms than the controls. We also found developmental changes in the performance of the WS group that were largely parallel to those seen for unimpaired children. Our conclusion is that apart from difficulties accessing irregular word forms in production, the inflectional system of people with WS is unimpaired.