The phonological component of a grammar determines the phonetic form of a sentence generated by the syntactic rules. That is, it relates a structure generated by the syntactic component to a phonetically represented signal [...] Both the phonological and semantic components are therefore purely interpretive.
- Chomsky (1969), Pag. 16

The phonological component consists of a sequence of rules that apply to a surface structure "from the bottom up" in the tree-diagram representing it. That is, these rules apply in a cycle, first to the minimal elements (formatives), then to the constituents of which they are parts [...] then to the constituents of which these are parts, and so on, until the maximal domain of phonological processes is reached.
- Chomsky (1969), Pag. 143