Constituent Structure - Part 24 | 120 PHRASE STRUCTURE GRAMMARS AND X-BAR We ll conclude this section with a little extra terminology that goes along with the notion of headedness and projection. Consider the NP in 29 . 28 NP D the N N PP N bag PP with the plastic handle of grocers Each of the N s and the NP in 28 are called the projections of the N. The NP is the maximal projection and the N s are intermediate projections. Modification relations are no longer expressed in terms of sisterhood to the head instead modifiers of a head are sisters to any projection of that head. Binarity The constituency tests we ve seen in this chapter and the rules given in 26 reveal another important property that X-bar theory might account for. It appears as if the layers of structure operate in a binary That is as we add layers of structure new material is added one element at a time to the existing structure thus creating a binary branching tree structure. The three X-bar statements mentioned above can be modified to capture this 29 a XP YP X b X ZP X c X X ZP d X X WP Instead of ellipses . we use the variable categories YP WP and ZP to stand in for the modifiers. These are listed as optional as the phrase can consist of a head without any modifiers at all. They are also all 10 See Chametzky 2000 for a discussion of how this insight is retained in the minimalist non-X-bar-theoretic Bare Phrase Structure system. X-BAR THEORY 121 listed as phrasal including the one in 29a which is typically occupied by a bare determiner. We will return to this contradiction below. Binarity is a common but by no means universal part of X-bar theory. Distinctions among modifier types Given our three types of rule which introduce three distinct layers of structure we predict that we should have at least three distinct types of head-modifiers. This appears to be true. We find good evidence that we need to distinguish among specifiers the YP in the XP YP X rule adjuncts the ZP in the X ZP X and X X ZP rules and .
