Syntax II

“I really do not know that anything has ever been more exciting than diagramming sentences.”

--Gertrude Stein

Quick Review• Syntax: the study of how words are put together to form sentences and phrases.

• These rules operate on lexical categories…

• independently of the meaning of the words.

• Lexical categories can be defined by:

• the syntactic distribution of words

• the types of inflectional affixes which may attach to them

• Lexical categories (noun, verb, adjective, preposition, etc.) were used to make the old game “Mad Libs” work.

The Last Quick Write• Mad Libs!

• The following sentence is both grammatical and (somewhat) sensible:

Colorless Green Libs?• These sentences are grammatical but don’t make that much sense:

Bad Libs.• The following sentences are not grammatical.

Bad Libs.• The following sentences are not grammatical.

Artsy Libs.• Some of you were quite enthusiastic about the exercise.

How does this work?• We know that words of different lexical categories have to fit together with the words in their environment to make a sentence grammatical.

• A first hypothesis--the rules for putting sentences together string one word category after another:

S Det N V Det N

( = “may consist of”)

The child found a puppy.

S Det A N V P Det N

The slithy toves gimbled in the wabe.

• These syntactic rules capture patterns of words.

Important Data• What’s going on in these sentences?

1. We need more intelligent leaders.

2. I like green eggs and ham.

3. The police shot the terrorists with rifles.

• Syntax also puts words together in units that are smaller than sentences.

• These units are called phrases.

• Same string of words, more than one interpretation =

• more than one phrase structure

• structural ambiguity

Ambiguity (again)• In order to represent phrase structure, we will use tree diagrams.

more intelligent leaders

more intelligent leaders

Phrases

• The nodes in a syntactic tree above the word level represent phrases.

• phrase = string of words that function as a unit

• Basic phrase types:

1. Noun Phrases (NP): [intelligent leaders]

2. Verb Phrases (VP): [shoot terrorists]

3. Prepositional Phrases (PP): [with rifles]

4. Adjective Phrases (AP): [more intelligent]

Phrase Phacts• Every phrase has to have at least one constituent

• This constituent is called the head of the phrase.

• The head determines the phrase’s function, behavior and category.

• For example, noun phrases have to consist of at least one noun.

Robin the book

a picture of Robin a picture of the unicorn

that weird picture of Bob’s unicorn

In General• There’s a pattern to how these things work:

• Noun phrases (NPs) are headed by nouns

• NP N

• Verb phrases (VPs) are headed by verbs

• VP V

• Prepositional phrases (PPs) are headed by prepositions

• PP P

• Adjective phrases (APs) are headed by adjectives

• AP A

• Basic Phrase Structure Rule: XP X

More About Phrases• Beyond the heads, phrases can be expanded with

specifiers and complements.

• Specifiers precede the head of the phrase;

• they pick out a particular version of the head.

• Examples:

1. this book (Determiner specifying noun)

2. very late (Degree word specifying adjective)

3. often forgets (Adverb specifying verb)

4. almost in (Degree word specifying preposition)

Complements• Complements always follow the head of the phrase…

• And provide more information about that head.

1. this book about unicorns

• PP complement of the head of the NP.

2. very late to class

• PP complement of the head of the AP.

3. often forgets his hat

• NP complement of the head of the VP.

4. almost in the basket

• NP complement of the head of the PP.

X-Bar Theory• Together, heads and their complements form a phrasal structure known X’ (“X-bar”).

• Here’s the way phrases (of all kinds) normally break down:

XP

(Specifier) X’

X (Complement)

Head

• note: heads are the only obligatory element in the phrase

• optional stuff is in parentheses

Tests for Phrase Structure• There are some tests you can use to figure out if a

group of words constitutes a phrase.

1. Substitution

• Phrases (and only phrases) can be substituted for by shorter expressions.

• Ex: Pronouns can be substitutes for NPs.

• The coach wanted a picture of the book.

• She wanted a picture of the book. (= the coach)

• The coach wanted it. (= a picture of the book)

• The coach wanted a picture of it. (= the book)

Tests for Phrase Structure• VPs can be substituted with the phrase “do so”.

• Ex: The coach dropped the ball, and the professor did so, as well. (= dropped the ball)

• PPs can be substituted with “there”.

• The children waited at the corner, and we waited there, too. (= at the corner)

• Substitutions do not work for non-constituents (or the wrong constituents):

• *The coach dropped the ball, and the did so, too.

• *The children waited at the corner, and we waited at there, too.

• *The coach dropped the it.

Tests for Phrase Structure2. Movement: sometimes, constituents can be moved to

another part of the sentence.

• NP movement: He hated the Jedi Knights.

• The Jedi Knights, he hated.

• Bad examples:

• *Jedi Knights, he hated the.

• *The Jedi, he hated Knights.

• VP movement:

• Hate the Jedi Knights, he did.

• PP movement: We ran up the hill.

• Up the hill, we ran.

Tests for Phrase Structure3. Coordination

• Conjunctions like {and, but, or} coordinate phrases of the same type.

• NP-coordination:

• I like [romantic sunsets] and [long walks on the beach].

• PP: We went [over the river] and [through the woods].

• VP: They want to [eat pizza] or [play video games].

• AP: The blizzard was [very intense] but [surprisingly short].

Tests for Phrase Structure3. Coordination

• Conjunctions like {and, but, or} coordinate phrases of the same type.

• Coordination of unlike phrases can sound quite bad:

• NP + AP: *I like [romantic sunsets] and [surprisingly short].

• PP + VP: *We went [over the river] and [play video games].

• VP + NP: *They want to [eat pizza] or [long walks on the beach].

• AP + PP: *The blizzard was [very intense] but [through the woods].

Example Tree

NP

Det N’

the N

book

How about: “a picture of the book?”

NP

Det N’

a N PP

picture P NP

of Det N’

the N

book

More Example Trees• Let’s draw trees for the following phrases:

• VP: often forgets his hat

• PP: almost in the basket

• AP: very late to class

A VP Example

VP

Adv V’

often V NP

forgets Det N’

his N

hat

An AP Example

AP

Deg A’

very A PP

late P NP

to N’

N

class

Check This Out1. A phrase structure rule for NPs looks like:

• NP Det N’

2. And a PP can be a complement of a head noun:

• N’ N PP

3. And an NP can be a complement of a prepositional phrase:

• PP (Deg) P’

• P’ P NP

• Where can this combination of rules take us?

Whoa, Nellie• There is a possibility for infinite recursion.

• NP Det N PP

• NP Det N P NP

• NP Det N P Det N PP

• NP Det N P Det N P NP

• NP Det N P Det N P Det N PP, etc.

• Example: the book from the library in the city near the airport beside the apartment complex with the playground of the children from the school behind the train tracks...

• The fact that our grammar can generate phrases like this is why we need to know patterns of patterns.