Resumen:
This article presents the results of an experiment designed to study the morphological abilities of typically developing children and those of children with Down syndrome. To do this, we used the Wug test and manipulated the final phoneme of the stimulus, consonant or vowel, to generate pseudoword plurals. The results indicated that children made more errors with the plural morpheme -es than with -s, suggesting a relationship between phonological processing and the application of the morphological rule. Children with Down syndrome made more errors than children from the 2 control groups (children matched by mental age and by vocabulary level), suggesting that the application of this rule is genuinely altered in these children and is not a result of their intellectual ability or vocabulary level.