Language and cognition are deeply intertwined, shaping how we think, communicate, and perceive the world. This unit explores the psychological and neurobiological factors that enable language acquisition, use, and understanding, as well as the cognitive processes involved in these linguistic abilities. From historical perspectives to modern theories, we examine how language and thought interact. We delve into the brain's role in language processing, research methods in psycholinguistics, and practical applications of this knowledge in fields like therapy, education, and technology.