Noun phrases (NPs) are versatile. They can perform several different syntactic functions (fill in several different grammatical slots) in a sentence.

Most often, NPs serve as the subject in a clause. However, they can also function as a direct object (DO), indirect object (IO), subject predicate (SP), object predicate (OP), and object of a preposition (OofP).

What function an NP fulfills in a clause depends on the type of lexical verb that precedes it (PP are exceptions). So, we need to pay close attention to the lexical verb in a clause.

1. Subject (Subj.):

In the sentences below, all the NPs function as the subject.

1) [Humans] | are prone to making mistakes.

2) [Those houses] | were built in the 1920s..

2) [Dogs and cats] | are excellent pets.

NP: Subj.

A subject is a nominal structure (a word, phrase, or clause) that names the agent, doer or source of what is done (who/what performs the action or acts upon the verb)

The subject of a sentence can be

1. animate humans and animals,

2. inanimate things, abstractions, and concepts,

3. rhetorical participants ('I' as the author), 'you' as the imaginary audience)

4. slot fillers (dummy 'it', 'there be' structure)

2. Direct Object (DO):

In the sentences below, all the NPs function as the DO.

1) Our friends | have bought [a new house].

2) Charlie | ate [all my croissants].

3) Lucky | caught [a bird].

NP: DO

A DO is a nominal structure (a word, phrase, or clause) that names the recipient or goal of an action (follows a transitive verb and answers the question “who?” or “what?” receives the action).

** Only transitive verbs can have a DO. Intransitive verbs and copular verbs do not have DOs.

Note: NP1[our friends] is called the agent and NP2 [a new house] the patient or recipient the action (VP [have bought]).

3. Indirect Object (IO)

In the sentences below, all the NPs function as the IO.

1) Can you pass [me] [the pepper]?

2) I | got [Zoey] [some treats].

3) Michelle | gave [me] [a tour of her house].

NP: IO

An IO is a nominal structure (a word, phrase, or clause) that follows a ditransitive verb and is acted upon indirectly by the verb (often a person).

** Only ditransitive verbs have an DO.

IO usually appear along with the DO. The IO is often a person and DO an object. The sentences above can be transformed as the following:

1) Can you pass the pepper to me?

2) I got some treats for Zoey.

3) Michelle gave a tour of her house to me. (grammatically correct buts sounds a bit weird)

4. Subject Predicate/complement (SP/SC)

In the sentences below, all the NPs function as the SP/SC.

1) My grandparents | are [farmers].

2) I | have been [a teacher] for twenty years.

3) She | is [the fastest runner] that I know.

NP: SP

A SP/SC a word, phrase, or clause that follows a copular (linking) verb and describes the subject of a clause.

** SP/SC only appear after copular verbs.

5. Object Predicate/complement (OP/OC)

In the sentence below, all the NPs function as the OP/OC.

1) People| consider their pets [family members].

NP: OP

An OP/OC is a noun, pronoun, NP, adjective, or an adjective phrase that directly follows and modifies the DO.

** Only a small number verbs can have an OP/OC.

6. Object of Prepositions/OofP

In the sentence below, all the NPs function as the OofP.

1) Artificial intelligence | can be scary [in [some sense]].

NP: OofP

An OofP is a word, phrase, or clause that directly follows a preposition and completes the preposition.

** In a PP, the NP that follows the preposition always functions as OofP.

8. Appositive

e.g., "The island of Gont, a single mountain that lifts its peak a mile above the storm-racked Northeast Sea, is a land famous for wizards." — Ursula LeGuin, A Wizard of Earthsea

9. Direct address e.g., Mickey, off the road.

9. Modifier e.g., Mickey is two months older than Charlie.