(Copyright © 2000 Piero Scaruffi | Legal restrictions - Termini d'uso )
In order to explain the difference between "performance" (all sentences that an individual will ever use) and "competence" (all sentences that an individual can utter, but will not necessarily utter), Chomsky posits the existence of some innate knowledge. Chomsky proved that the grammar of a natural language cannot be reduced to a finite-state automaton. Later, Gold proved that no amount of correct examples of sentences are enough to learn a language.
Chomsky argues for the existence of two levels of language: an underlying deep structure, which accounts for the fundamental syntactic relationships among language components, and a surface structure, which accounts for the sentences that are actually uttered, and which is generated by transformations of elements in the deep structure. Transformational analysis does overcome the limitations of phrase structure.
Chomsky's "standard theory" defines a grammar as made of a syntactic component (phrase structure rules, lexicon and transformational component), a semantic component and a phonological component. The lexicon is modeled after Katz's lexicon. Context-sensitive rules determine the legal positions in the sentence of lexical items. The semantic component is also inspired by Katz, as it uses projection rules and semantic markers.
The deep structure of a sentence is a tree (the phrase marker) that contains all the words that will appear in its surface structure.
Chomsky starts coupling syntax and semantics when including an account of the relation between sound and meaning in the construction of a grammar. The "standard theory" syntax provides the mechanisms for transforming a meaning (a deep structure) into a phonetic representation (a surface structure).
Chomsky decomposes a user's knowledge of language into two components: a universal compenent (universal grammar), which is the knowledge of language possessed by every human, and a set of parameter values and a lexicon, which together constitute the knowledge of a particular language.