Examining language development in syndromes with identifiable genetic causes is particularly helpful for identifying the ways in which language and cognition can influence one another. R. Chapman, H.-K. Seung, S. Schwartz, and E. Kay-Raining Bird suggested that the expressive language skills of children and adolescents with Down syndrome (DS) are more delayed than would be expected based on levels of nonverbal visual cognition. In addition, cross-syndrome comparisons can help us to determine whether challenges to language development are due to intellectual disability and cognitive delay, more generally, or are syndrome-specific. The language impairments associated with 22q11.2DS may play a role in the emergence of schizophrenia and psychotic symptoms, which are highly prevalent in adolescents and adults with the syndrome. The language of males and females with fragile X syndrome is affected similarly, with quantitative differences that are related to differences in nonverbal cognition.