In this chapter, we focus on language development in individuals suffering from language and cognitive disorders. One of the major concerns of families and caregivers of individuals with these disorders is that exposure to more than one language may cause further difficulties, slow down, or hinder linguistic and cognitive development. Scientific research, however, shows that this is an unmotivated prejudice, and that bilingualism does not provide negative effects, but rather, can offer benefits. We explore the interaction between bilingualism and language disorders, discussing in particular developmental language disorders, developmental dyslexia, autism spectrum disorders, hearing loss, Down syndrome, and aphasia.