Phrase structure rules

Phrase structure rules: rules stating that the structure of a phrase of a specific type consists of one or more constituents in a particular order.

First rule: “a sentence (S) rewrites as a noun phrase (NP) and a verb phrase (VP).” 

S → NP VP 

EX: Sentence: "She wants him to leave."

Step-by-Step Analysis:

• V (Verb): "Wants"

• NP (Noun Phrase): "Him" (the object of the verb "wants")

• VP (Verb Phrase): "To leave" (infinitive complement of "wants")

Second rule: “a noun phrase rewrites as either an article plus an optional adjective plus a noun, or a pronoun, or a proper noun.” 

NP → {Art (Adj) N, Pro, PN} 

EX: Example 1: "The big dog"

• Art: "The"

• Adj: "Big" (adjective modifying the noun)

• N: "Dog"

• Noun Phrase: "The big dog"

Third rule: a verb phrase rewrites as a verb plus a noun phrase. 

VP → V NP 

EX: Sentence: "She eats an apple."

• V (Verb): "Eats"

• NP (Noun Phrase): "An apple"

  • Art (Article): "An"

  • N (Noun): "Apple"