In the field of linguistics

Linguistics

Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

, specifically in syntax

Syntax

In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....

, phonetic form (abbreviated 'PF'), refers to a certain level of mental representation

Mental representation

A representation, in philosophy of mind, cognitive psychology, neuroscience, and cognitive science, is a hypothetical internal cognitive symbol that represents external reality, or else a mental process that makes use of such a symbol; "a formal system for making explicit certain entities or types...

 of a linguistic expression, derived from surface structure, and related to logical form

Logical form (linguistics)

In the field of linguistics, particularly in the minimalist program, Logical Form , refers to a mental representation of a linguistic expression, derived solely from Surface Structure. In the words of Chomsky, LF captures "those aspects of semantic representation that are strictly determined by...

. Phonetic form is the level of representation wherein expressions, or sentences, are assigned a phonetic representation, which is then pronounced by the speaker. Phonetic form takes surface structure as its input, and outputs an audible (or visual, in the case of sign languages), pronounced sentence.