What is universal grammar in linguistics?

Universal Grammar is a theory in linguistics that suggests that the ability to acquire language is innate to humans, and that humans are born with an inherent knowledge of the structure and rules of language. Proposed by Noam Chomsky, this theory suggests that all languages share a common underlying structure, and the differences between languages are variations within this universal grammar. According to this theory, humans are biologically predisposed to learn languages and have an inherent understanding of grammar, which allows them to acquire any language they are exposed to during their early years. Universal Grammar theory has had a significant influence on the study of linguistics and language acquisition.