" The surface structure consists of the actual words in it and the order in which they occur. The deep structure has to do with fundamental syntactical relationships underlying these words; in other words, the deep structure concerns the intended meaning or the thoughts conveyed by language (Chomsky, 1957, 1965).
Chomsky devised a model of "transformational grammar" to convert underlying, deep structure into the surface structure of a sentence and proposed that people understand sentences by transforming the surface structure into a basic, deep structure or kernel form. Also, they use transformational rules to convert deep structure to surface structure ding speech production or writing. What is learned, therefore, is not a string of words but transformational rules that enable the speaker to generate an infinite variety of novel sentences and enable a listener to understand the infinite variety of sentences heard.
In summary then, Chomsky suggests that the transition in language learning from the simple stages of comprehension and expression to the stage at which the child uses a complex mechanism of language is so complex that some important aspects of language cannot be learned but are innate within the brain. His theory views language learning as similar to learning to walk; rather than being completely acquired, some aspects of spoken language "unfold" under appropriate developmental an