This chapter focuses on developmental language disorders in bilingual children and on acquired language disorders in bilingual adults. It provides some general issues in relation to communication disorders in bilingual children and adults and also focuses on those that impact language primarily. The chapter reviews aphasia, an acquired primary language disorder, as well as two degenerative diseases, Alzheimer’s disease and Parkinson’s disease, which result in communication disorders. Language disorders in bilingual children and adults provide information on how language contact alters the development and representation of the disorders. Bilingualism helps to improve metalinguistic skills, and executive function; therefore, it is possible that bilingual children with primary language impairment may have an advantage in developing metalinguistic and cognitive skills important for communication. Bilingualism in children can occur in additive and subtractive-language environments. As with grammatical skills, bilingualism can cause some differences in processing skills and executive function skills.