(Copyright © 2000 Piero Scaruffi | Legal restrictions - Termini d'uso )
Chomsky's standard theory assumed that each sentence exhibits a surface and a deep structure. Many sentences may exhibit the same deep structure (e.g., active and passive forms of the same action). Understanding language consists in transforming surface structures into deep structures.
These transformations can be seen as corresponding to mental processes, performed by mental modules, each independent of the others and each guided by elementary principles.
Fundamental to his theory is the belief that there exist "innate structures", that the ability to understand and utter language is due to a "universal grammar" that is common to all humans and is somewhow encoded in the human genome. Then experience "selects" the specific grammar that the individual will learn. Grammar is learned not in stages, as Piaget thought, but simply by gradually fulfilling a blueprint that is already in the mind.
Children do not learn, as they do not make any effort. Language "happens" to a child. The child is almost unaware of the language acquisition process. Learning to speak is not different from growing, maturing and all the other biological processes that occur in a child. A child is genetically programmed to learn a language, and experience will simply determine which one. The way a child is programmed is such that all children will learn language the same way.
Chomsky also notes how the language spoken by a linguistic community is so identical to the smallest detail, even if no individual of the community has been exposed to all the smallest details.
The universal grammar is the linguistic genotype. Its principles are invariant for all languages. The values of some parameters can be "selected" by the environment out of all valid values. This process is similar to what happens with other growth processes (e.g., with the immune system).