What is Syntax?

Syntax refers to word order and depends on lexical categories (parts of speech.) You probably learned that there are eight main parts of speech in grammar school. Linguistics takes a different approach to these categories and separates words into morphological and syntactic groups. Linguistics analyzes words according to their affixes and the words that follow or precede them. Hopefully, the following definitions of the parts of speech will make more sense and be more useful than the old definitions of grammar school books.

Open Class Words

Nouns	_____ + plural endings "dogs"	Det. Adj. _____ (this is called a Noun Phrase) "the black cat"
Verbs	____ + tense endings "speaks"	Aux. ____ (this is called a Verb Phrase) "is talking" / "have eaten"
Adjectives	____ + er / est "small"	Det. ____ Noun "the young child"
Adverbs	Adj. + ly "quickly"	____ Adj. or Verb or Adv. "quickly answered"

Closed Class Words

Determiners	a, an, the, this, that, these, those, pronouns, quantities	____ Adj. Noun "this heavy book"
Auxiliary Verbs	forms of be, have, may, can, shall	NP ____ VP "the boy is singing"
Prepositions	at, in, on, under, over, of	____ NP (this is called a Prepositional Phrase) "in the drawer"
Conjunctions	and, but, or	N or V or Adj. ____ N or V or Adj. "desks and chairs"

Subcategorization defines the restrictions on which syntactic categories (parts of speech) can or cannot occur within a lexical item. These additional specifications of words are included in our mental lexicon. Verbs are the most common categories that are subcategorized. Verbs can either be transitive or intransitive. Transitive verbs take a direct object, while intransitive verbs take an indirect object (usually they need a preposition before the noun).

Transitive verb: to eat	I ate a pear. (direct object)
Intransitive: to sit	I was sitting on the chair. (indirect object)

Individual nouns can also be subcategorized. For example, the noun idea can be followed by a Prepositional Phrase or that and a sentence. But the noun compassion can only be followed by a Prepositional Phrase and not a sentence. (Ungrammatical sentences are marked with asterisks.)

the idea of world peace	his compassion for the poor
the idea that world peace is necessary	*his compassion that the poor are hungry

Phrase structure rules describe how phrases are formed and in what order. These rules define the following for English:

Noun Phrase (NP)	(Det.) (Adj.) Noun (PP)
Verb Phrase (VP)	Verb (NP) (PP)
Prepositional Phrase (PP)	Prep. NP
Sentence (S)	NP VP

The parentheses indicate the categories are optional. Verbs don't always have to be followed by prepositional phrases and nouns don't always have to be preceded by adjectives in English. (These rules only apply to English - other languages have different phrase structure rules!)

Passive Sentences
In order to change an active sentence into a passive one, the object of the active must become the subject of the passive. The verb in the passive sentence becomes a form of "be" plus the participle form of the main verb. The subject of the active becomes the object of the passive preceded by the word "by."

Active	Passive
The dog saw the cat.	The cat was seen by the dog.
Subject + Verb + Object	Object + "be" + Verb + by + Subject