Knowledge of Syntax

Phrase Structure Grammars

Intuitions About Grammaticality

• Syntax – a system whose primitive terms are non-

semantic and non-discourse derived and whose principles of combination make no reference to system external factors.

Autonomy of Syntax

• Syntax and Semantics are independent.• The structure of language is

autonomous from the meaning.– “Colorless green ideas sleep furiously.”– Compare:

a.“Furiously sleep ideas green colorless.”b.“Revolutionary new ideas occur infrequently.”

Autonomy of Syntaxa. He is likely going to be late.b. He is probably going to be late.

c. He is likely to be lated. *He is probably to be late.

e. He allowed the rope to go slack.f. *He let the rope to go slack.

g. He isn’t sufficiently tall.h. *He isn’t enough tall.

Autonomy of Syntax

• We all share a strong sense as speakers of English that these sentences are ill formed, but that they are also clearly interpretable. So whatever it is that lets us know that they are structurally flawed is autonomous from whatever it is that let's us understand their intended meaning.

Autonomy of Syntax

• Sometimes sentences have two meanings, leading us to believe that they must have two structures.

• Ambiguous sentences:– Kate saw the man with the telescope– Visiting relatives can be tedious.– The President gave the Chinese dolls.

Trees in Syntax

• The lines in the trees are branches.• The end of any branch is a node.• M is the root node (no branches above it)• N is the mother of D, E, and F.• D, E, F, H, I, and J are terminal nodes (no branches below them).

M

N

D E F

O

H I J

Trees in Syntax

• Syntactic trees are just a graphical variant of labeled brackets.

N

D E F

= [N D E F ]N

Dominance is another way of expressing inclusion in a set.

Phrasal Structure

• Consider: Kate saw the man with the telescope. • It’s pretty intuitive that the telescope is a

linguistic unit:

the telescope

art noun

NP

What did Kate see the man with?

Phrasal Structure

• The basic idea is that the is classified as an article, and telescope is a noun, and the entire thing is a Noun Phrase.

the telescope

art noun

NP This is a constituent

Phrasal Structure

• Let’s take a slightly larger unit:

the telescope

art N

NP

with

PP

P

This is a Prepositional Phrase (PP), with the preposition with (P). The constituent the telescope is contained within the PP.

How did Kate see the man?

Phrasal Structure

• Continuing to build up the structure:

the telescope

art N

NP

with

PP

P

the man

Nart

NP

NP

Who did Kate see?

Phrasal Structure• Continuing up:

the telescope

art N

NP

with

PP

P

the man

Nart

NP

NP

saw

V

VP What did Kate do?

Phrasal Structure

the telescope

art N

NP

with

PP

P

the man

Nart

NP

NP

saw

V

VP

Kate

N

NP

S

“Kate saw the man carrying a telescope.”

Constituent

Phrasal Structure

the telescope

art N

NP

with

PP

P

the man

Nart

NP

saw

V

VP

Kate

N

NP

S

“Kate used a telescope to see the man.”

No constituent that dominates only the man with the telescope.

Memory

• I said that Markov Grammars have no ability to explain dependencies that are non-local:– The dog sleeps.– The dogs sleep.

• Subject-verb agreement. But what about: – The dog in the kennel sleeps.

Phrasal Structure

the kennel

art N

NP

in

PP

P

the dog

Nart

NPsing

NP

sleeps

V

VPsing

S

Phrasal Structure

the kennel

art N

NP

in

PP

P

the dogs

Nart

NPpl

NP

sleep

V

VPpl

S

Phrase Structure Rules

• The sentence (clause):1. S NP VP

• This rule says that every sentence consists of a noun phrase (NP) and a verb phrase (VP).

• Rule (1) corresponds to the traditional notion of subject and predicate.

Exercise

– This is a novel.– He feels empty.– So that was that.– Unfair’s unfair.– Nat was Nat.

– Work was his life.– Creators are workaholics.– Music was my refuge.– Space was the real

problem.– I was all humility.

Tufte, pp. 10-13

• Divide these short sentences into NP and VP:

This is a novel.

isThis

NP

N V

VP

S

a novel

N

NP

art

He feels empty.

feelsHe

NP

N V

VP

S

empty

AP

Adj

Creators are workaholics.

areCreators

NP

N V

VP

S

workaholics

NP

N

Exercise

• Draw trees for the following sentences:– Nat was Nat.– Work was his life.– Music was my refuge.– I was all humility.

A Question

• Why do we group the V with the second NP in the sentence? What’s the evidence for that?

• Constituency tests: NP V never acts as a unit.– What did he do? Feel empty. (Question)– What did empty? *He feel.– It was feel empty that he was. (Cleft)– *It was he feel that (was) empty.

Productivity

• We are able to make infinitely long sentences.

• Markov Grammars gave us a way to do that:

dog

dogs

snores

snore

The old● ●

●

●

●●

very

Productivity

• Different kinds of productivity:– The very, very, very, …, old dog snores.– The dog that chased the cat that ate the

rat…– I believe that you know that she thinks that

they doubt…– The apple on the table in the house on the

street in the town by the lake in the country on the planet…

Trees and Rules

N

NP

art

= N art N

Trees and Rules

• We’ve seen trees that represent the following set of rules:

1. S NP VP2. N art N3. VP V NP4. VP V AdjP5. AdjP Adj6. VP V NP PP7. PP P NP

Exercise

• Draw the Phrase Structure tree that is defined by the PS rules below:

1. S NP VP2. NP Art N3. VP V NP PP4. NP Art N5. PP P NP6. NP Art N

• Be sure to apply the rules in order (1-6).

Lexicon

• The terminal nodes can be replaced with lexical items:– Nouns = cat, dog, ice cream, bananas, avocados– Verbs = like(s), eat(s), – Art = a, the, my, this, that, one, all– P = in, on, at, under, with

• Add lexical items to your tree structure.

Exercise

• Consider the following sentences:– Space was the real problem.– War remains the decisive human failure.– The myth of war creates a new, artificial

reality.• What rule are we missing to account for

these sentences?

NP Art Adj N

wasSpace

NP

N V

VP

S

real

NP

AdjArt N

the problem

Phrase Structure Rules• Productivity in a PS grammar comes from

the ability of rules to combine into an infinite sequence:1. NP NP PP2. PP P NP NP

NP PP

P NP

NP PP

P NP …

Phrase Structure Rules

• This can apply to different types of rules:1. S NP VP2. VP V S S

NP VP

V S

NP VP

V S …

Exercise

• What rules would you use to account for this type of productivity?– The dog that chased the cat that ate the

rat…

More Ambiguities

• Draw phrase structure trees for the following ambiguous sentences:– Visiting relatives can be tedious.– The President gave the Chinese dolls.– The hungry bear fishes.