Noun phrase

Some examples of noun phrases are underlined in the sentences below. The head noun appears in bold.

Noun phrases can be identified by the possibility of pronoun substitution, as is illustrated in the examples below.

A string of words that can be replaced by a single pronoun without rendering the sentence grammatically unacceptable is a noun phrase. As to whether the string must contain at least two words, see the following section.

On this understanding of phrases, the nouns and pronouns in bold in the following sentences are noun phrases (as well as nouns or pronouns):

For illustrations of different analyses of noun phrases depending on whether the DP hypothesis is rejected or accepted, see the next section.

The representation also depends on whether the noun or the determiner is taken to be the head of the phrase (see the discussion of the DP hypothesis in the previous section).

1. Phrase-structure trees, first using the original X-bar theory, then using the current DP approach:

 NP NP | DP DP / \ | | / \ |
det N' N' | det NP NP | / \ / \ | | / \ / \
the adj N' adj N' | the adj NP adj NP | | | | | | | | | big N big N | big N big N | | | | | house houses | house houses

2. Dependency trees, first using the traditional NP approach, then using the DP approach:

 house houses | the (null) / / / | \ \ / / big | house houses the big | / / | big big

The first tree is based on the traditional assumption that nouns, rather than determiners, are the heads of phrases.

The second tree assumes the DP hypothesis, namely that determiners rather than nouns serve as phrase heads.