This chapter examines the multifaceted nature of language as a core component of human cognition. It begins with language acquisition and development, outlining developmental stages—from prelinguistic vocalizations to complex, rule-governed language use—and reviews key theoretical frameworks, including nativist and social interactionist perspectives. The chapter further explores the structural dimensions of language, detailing subdisciplines such as phonetics, phonology, morphology, syntax, semantics, and pragmatics, and their corresponding neurobiological bases. Furthermore, it discusses the processes of language comprehension and production, emphasizing how these interrelated mechanisms enable effective communication. Finally, the chapter addresses bilingualism and second language acquisition, highlighting both the cognitive advantages of managing multiple languages and the diverse theories that explain how additional languages are learned. Throughout, the discussion integrates insights from neurolinguistics and cognitive psychology, illustrating the dynamic interplay between innate predispositions and environmental influences in shaping linguistic competence.