projection (n.)

A term used in GENERATIVE LINGUISTICS to characterize the capability of a GRAMMAR to extend the analysis of any given set of SENTENCES so that it applies also to the potentially infinite number of sentences in the LANGUAGE as a whole. The main means of doing this is the generative RULE. In some MODELS of generative grammar, a more restricted sense is found: projection rules are established as part of the SEMANTIC COMPONENT, their function being to assign a semantic INTERPRETATION to each STRING of FORMATIVES generated by the SYNTACTIC component.

A central principle of GOVERNMENT-BINDING THEORY is the projection principle, which projects the properties of LEXICAL entries on to the STRUCTURE of the sentence. It states that the SUB-CATEGORIZATION requirements of lexical items must be satisfied at all levels of REPRESENTATION. It eliminates the need for rules combining lexical items with their COMPLEMENTS, and requires a TRACE to be left when a complement is removed. The extended projection principle requires that all sentences must have a subject. In X-BAR syntax, phrasal projections (or bar projections) refer to the different types of phrasal expansion of any word-level category: a SINGLE-BAR projection into a ‘small’ X-bar phrase, and a DOUBLE-BAR projection into a ‘large’ X-double-bar phrase. All full phrases (e.g. AP, NP, PP) are maximal projections – levels above which the properties of the lexical entries for the HEADS have no influence. In a later development, IP and CP are viewed as extended projections of V, and DP and PP as extended projections of N. In the grid and bracketed-grid theories of METRICAL PHONOLOGY, ‘projection’ refers to the introduction of a new line in the grid.