Noun

• exclusively denotes a person place or thing
• also can denote actions, properties, relations, concepts, etc. (almost anything really)
• may participate in the system of number
  may be countable
  may have a plural form
• functions as head of NP
• may take a determiner as its dependent
• may be modified by an AdjP

NP

• Typically functions as subject or object
• usually headed by N

Verb

• denotes actions and states, but not physical objects
• usually has a 3rd person singular -s form
• has a past-tense form, apart from 2 or 3 highly defective verbs
• has an -ing form, apart from the modal auxiliary verbs
• functions as head of VP
• cannot be modified by an AdjP

VP

• functions as head of clause
• functions as modifier in NP
• functions as complement in VP, NP, AdjP, and PP
• headed by V

Clause

• Headed by VP
• Typically has a subject

Adjective

• denotes properties or characteristics, but not objects
• may have a comparative -er and superlative -est form (especially single-syllable Adj)
• functions as head of AdjP
• may be modified by very, too, and so
• may be graded with more, less, most, and least

AdjP

• functions as modifier in NP
• functions as complement to be, seem, and become
• doesn't function as modifier in VP
• headed by Adj

Determinative

• functions as head of DP
• usually has only one form (unlike pronouns)
• marks NP as definite or indefinite
• usually cannot occur together with the or a
• usually can appear in this slot: __ of the N (e.g., some of the people, each of the pencils)
• may be modified by other determinatives (e.g., many more people)

DP

• typically functions as determiner
• can sometimes function as modifier in DP, AdjP, or AdvP
• headed by D

Adv

• functions as head of AdvP
• often formed from Adj + -ly (happily)
• often gradable (well, better, best; quickly, more quickly, most quickly)
• usually modifiable by very

AdvP

• functions as modifier of almost any constituent except N, but including NP
• Rarely function as complement
• Rarely takes complements
• headed by Adv

Preposition

• typically denotes relations in space or time
• functions as head of PP
• usually has no suffixes or prefixes
• usually has only one form
• typically takes Obj:NP as its complement
• takes a variety of complements, including PP (out of…), Clause (before I arrived), & AdjP (for free), or no complement at all
• may be modified by AdvP, especially even, right, just, and almost
• Not typically modified by degree modifiers like very, too, and pretty.

PP

• functions as complement in VP, PP, NP, & AdjP
• functions as modifier in Clauses, VP, & NP
• very rarely functions as subject
• headed by P

Functions

Here’s a hierarchy of syntactic functions:

As you can see, Heads are special: everything else depends on them. As a result, everything else is a dependent. So far, we’ve seen four main kinds of dependent.

Subjects

• A subject is a dependent in a clause
• The subject typically occurs before the head verb.
• In certain kinds of questions, the subject occurs after an auxiliary verb.
• The subject is usually the topic of the sentence.
• If there is an action, it’s usually the person or thing doing the action.
• If there is a present-tense verb, it typically agrees with the subject.
• The subject is usually an NP, but Subj:Clause is also common, and Subj:PP is possible.

Determiners

• A determiner is only and always a kind of dependent in an NP.
• An NP will never have more than one determiner (though other NPs inside the NP may have their own determiners).
• Determiners are (almost) always determinatives or possessive NPs.
• A singular countable noun needs a determiner to form an NP.
• Determiners typically come before modifiers in the NP.

Complements

• Complements are so named because they often "complete" a phrase.
• Almost any kind of phrase can be a complement, though AdvPs complements are rare.
• Complements usually follow their head. In contrast, modifiers can often move around (e.g., the modifier quickly can go at the beginning, middle, and end of she changed direction).
• Complements are "selected" by their head (e.g., listen to the music not *listen about the music) .
• Phrases about where or when the situation happens or holds are typically modifiers, not complements.
• A modifier usually will not occur between a head and a complement.
• There can be zero, one, or two complements. A very small number of verbs take three complements (e.g., I bet you $100 that you will be a good teacher).
• Unfortunately, the boundary between complements and modifiers can be very fuzzy.

Objects

• Objects are dependents only in VPs or PPs.
• Objects are almost always NPs.
• If there’s an action, the object is usually what is acted on.
• The object of an active sentence is usually the subject of the related passive sentence (e.g., I made the cake --> the cake was made).

Modifiers

• Modifiers appear in most kinds of phrases.
• Typical modifiers are AdjPs and AdvPs, but almost any phrase can function as a modifier.
• Modifiers are quite flexible.
• Modifiers can often be removed without significant change of meaning.
• Modifiers can almost always be added or removed without affecting grammaticality.
• The number of modifiers is typically unlimited.
• Unfortunately, the boundary between complements and modifiers can be very fuzzy.