Syntax 1
Ling400
What is syntax?
• the study of the internal structure of
sentences: how to put together words to
form sentences
• Noam Chomsky’s theory of syntax:
accounts for the productivity of our
utterances in terms of structure-building
rules (phrase structure rules)
Chomsky’s Thesis
• We can utter and/or understand an
infinite number of sentences.
• We can do this despite the fact that our
brain can store only a finite amount of
information. We have a rule system (i.e.
grammar) in our brain.
• But we are not born with English
grammar. It is acquired.
Chomsky’s Thesis (continued)
• We are born with a system (called
Universal Grammar) which enables us
to acquire any language to which we
are exposed.
• By studying grammars of various
languages, we get insight into how
Universal Grammr is structured.
Syntax is independent of
Semantics (though related).
• Colorless green ideas sleep furiously.
(grammatical but semantically deviant)
• *Furiously sleep ideas green colorless.
(ungrammatical and meaningless)
• *The boy quickly in the house the ball
found.
(ungrammatical but meaningful)
How do we start?
• We rely on our grammaticality
judgments in doing syntactic study.
• We strive to propose a system that
produces all and only grammatical
sentences in English (or any other
lang.)
Syntactic Categories
• Knowledge of language
– Represented by your syntactic knowledge
• Syntactic categories
– Lexical categories (i.e. word-level categories):
noun, verb, adjective, preposition, etc.
– Phrasal categories: NP, VP, AP, PP, etc.
• Phrase structure
– Syntactic composition of phrases
– Structural ambiguity
Constituents
• A set of adjacent words that can form a
meaningful unit and can be replaced by
a pro-form (e.g. pronouns) and/or
moved as a unit are said to form a
constituent.
• A constituent can consists of just one
word or multiple words.
Lexical Categories
• The boy sees some very pretty flowers.
– perceives
– smells
• He puts the flowers on
– purple hydrangeas under
lovely
small
a
green table.
pink
poster
• Noun Verb
Preposition
Adjective
• There are four major syntactic categories of
open-class lexical items.
Syntactic categories
• Lexical categories: N, V, A, P, Det, etc.
• Phrases: NP, VP, AP, PP
(XP reads ‘X phrase, where X is the
“main item”. We will study this in detail
on Wednesday.)
• Constituents may be represented
hierarchically as trees.
How to find constituents
Subj. verb. Obj.
John met Mary.
The tall boy met the tall girl.
A boy from Seattle met a girl from Chicago.
A boy from Seattle met the tall girl.
John met a student who majors in mathematics.
What is subject? Something that the main verb agrees
with.
rules of thumb
•
•
•
•
answers to questions
substitution (pronouns, names, do, etc.)
clefting (It was … that …)
coordination
Two Types of Ambiguity
• Ambiguity = multiple meanings
• Lexical Ambiguity
– I’ll meet you by the bank.
• 1. A financial institution
• 2. A river bank.
• Structural Ambiguity
– due to different syntactic structures
associated with the same “string of words”
Structural ambiguity
I hate raw fish and onions
Give an unambiguous paraphrase.
Structural ambiguity
I hate raw fish and onions
Structural ambiguity
I hate raw fish and onions
Give a second unambiguous paraphrase.
Structural ambiguity
I hate raw fish and onions
Structural ambiguity
The price includes soup or salad and french fries
Draw two distinct trees for the blue
portion of the sentence.
Then provide paraphrases.
Structural ambiguity
The price includes soup or salad and french fries
For this price, you get french fries. And you can
also get soup or salad.
Structural ambiguity
The other possibility? Draw a tree and
provide a paraphrase.
The price includes soup or salad and french fries
Structural ambiguity
The price includes soup or salad and french fries
For this price, you get soup. Alternatively, you get
salad and french fries.
More examples of structural
ambiguity
(1)I killed the king with a knife.
ambiguous
(2) I killed the king with the red hair.
unambiguous