"The principles that determine the form of grammar and that select a grammar of the appropriate form on the basis of certain data constitute a subject that might, following a traditional usage, be termed “universal grammar.”
The study of universal grammar, so understood, is a study of the nature of human intellectual capacities.
It tries to formulate the necessary and sufficient conditions that a system must meet to qualify as a potential human language, conditions that are not accidentally true of the existing human languages, but that are rather rooted in the human “language capacity,”
and thus constitute the innate organization that determines what counts as linguistic experience and what knowledge of language arises on the basis of this experience.
Universal grammar, then, constitutes an explanatory theory of a much deeper sort than particular grammar, although the particular grammar of a language can also be regarded as an explanatory theory."
Language and Mind
Noam Chomsky
Nude Academy