This chapter describes how the quality and quantity of language input affects both children’s language ability and their cognitive control development. A nuanced exploration of the distinctions between input and intake as well as between input and exposure points to a complex pattern of interactions among these components and children’s communicative skills. The interactions among parental input, language environment, and the child’s age, as well as communicative abilities are bidirectional and affect children’s cognitive control skills, particularly working memory and interference control. The dynamic nature of caregiver – child interactions is also reflected in the manner parents adjust their language input based on their children’s communicative abilities. Parents of children with superior language skills used more elaborated language than did the parents of children with language delay, but those who participated in parental intervention increased the language and cognitive stimulation of their children.