Purpose: The current study addresses a gap in the literature regarding syntactic development of adolescent boys with fragile X syndrome (FXS) and Down syndrome (DS). Specifically, we ask whether syntactic skills plateau or continue to change during adolescence for these groups and whether the profile of syntactic change differs between boys with…

Researchers consistently report that children from low socioeconomic status (SES) families have, on average, smaller vocabularies as assessed by measures of existing vocabulary knowledge than children from higher SES families. Yet, few studies have examined the word-learning process of children from low SES families. The present study was an…