Language systems and their internal organisation
In his book Language and Mind (the third edition), Noam Chomsky mentions some of the classical ideas regarding language system and its internal structure. "It seems clear that we must regard linguistic competence- knowledge of a language- as an abstract system underlying behavior, a system constituted by rules that interact to determine the form and intrinsic meaning of a potentially infinite number of sentences."
He continues to point out that "such a system – a generative grammar - provides an explication of the Humboldtian idea of 'form of language,' which in an obscure but suggestive remark in his great posthumous work, Über die verschiedenheit des Menschlichen Sprachbaues, Humboldt defindes as 'that constant and unvarying system of processes underlying the mental act of raising articulated structurally organized signals to an expression of thought.' Such a grammar defines a language in the Humboldtian sense, namely as 'a recursively generated system, which the laws of generation are fixed and invariant, but the scope and the specific manner in which they are applied remain entirely unspecified.”'"
According to Chomsky, in each such grammar there are particular, idiosyncratic elements, selection of which determines one specific human language; and there are general universal elements, conditions on the form and organization of any human language, that form the subject matter for the study of “universal grammar.” Among the principles of universal gammar are the principles that distinguish deep and surface structure and that constrain the class of transformational operations that relate them. (Source:Chomsky, Noam (2006). Language and Mind, 3rd edition, Cambridge University Press, pp.62)