Children move from babbling to complex sentences in a few short years. Language acquisition is the process by which humans develop the ability to comprehend and produce language, especially the natural mastery of a first language in childhood.

Acquisition proceeds through stages affecting sounds, words, grammar, and pragmatic skills. Caregiver input, interaction, and general cognitive growth all contribute; theories disagree about how much structure is innate. Second-language acquisition in later life shares some processes but differs in route and typical outcome.

Researchers record spontaneous speech, run comprehension experiments, and compare diverse languages. Findings inform education, speech-language pathology, and theories of mind. Typical acquisition is robust even under imperfect input.

• Process of learning to use language
• Especially natural first-language development in children
• Proceeds through identifiable stages
• Informs teaching and cognitive science