"Deep structure" and "surface structure" are two terms coined by notorious linguist and scholar Noam Chomsky to describe the language production process.

Deep structure concerns itself with the internal understanding of language. All languages have the same deep structure, because almost all human beings have the same neurological processes of understanding. Deep structure is composed of three miniature structures which allow humans to process information. The semantic system gives us the ability to understand the explicit and implied meaning of individual words, the schematic system enables us to comprehend themes and ideas across entire texts, and the pragmatic system empowers us to alter words for specific purposes and audiences.

The surface structure is the form that these internal understandings take when produced in oral or written context. Although human beings possess the same methods of internal understanding, the ways in which they express these understandings vary greatly across countries, cultures, and, of course, languages. Surface structures are also composed of three micro-components. The graphophonic system facilitates understanding at the letter and sound levels, the lexical system consists of visual recognition of words due to repeated exposure, and the syntactic system begets understanding at the sentence and paragraph level.

The fact that languages take the same deep structure and transform it into diverse surface structures is one of the reasons why the study of linguistics has fascinated scholars for centuries.