T-model

Definition
The T-Model is a model of grammar prevalent in the Principles and Parameters framework, which has the general structure in (i):

(i)			DS | 			SS / \ 		     PF	   LF

It is usually assumed that, in English, DS ( D-structure) is generated by rewrite rules, or is projected from the rules of X-bar theory, and obeys the conditions of theta-theory and the Extended Projection Principle. SS ( S-structure) is derived from DS by the repeated application of affect alpha (e.g. NP-movement and Wh-movement ), and must meet the demands of Case theory, and possibly Binding Theory. LF ( Logical Form) is derived from SS through the application of affect alpha (e.g QR, Wh-raising (see Wh-in-situ)), and is regarded as the interface with the conceptual system; possibly, LF obeys Binding Theory and is the locus of gamma-checking ( gamma-marking). PF is derived from SS and is considered the interface with the articulatory-perceptual system. Both PF and LF are subject to the principle of Full interpretation. The division of labor among the three syntactic levels of representation (DS, SS, LF) is subject to debate, and may vary across languages.

Links

 * Utrecht Lexicon of Linguistics