Transcript Lecture 06

Lecture 6
Syntax
The Analysis
of Sentence Structure
Syntax
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Language use involves a rather complex system
of subconscious grammatical knowledge.
This is revealed most obviously in the study of
how words are combined to form sentences.
In this lecture, we will consider the system of
rules and categories underlying sentence
formation in human language.
This component of grammar is called syntax.
Grammaticality
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a.
b.
Like other linguistic systems, the syntactic
component of the grammar is both creative
and systematic:
i. Speakers of a language are able to
combine words in novel ways.
ii. However, combination is not chaotic .
Thus, we accept and comprehend some
sentences but reject others:
The student read a book.
*Book read student the a.
Categories
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Words can be grouped together into a small
number of classes.
These classes are called syntactic categories.
The classification assumes a number of factors:
i. meaning
ii. inflection
iii. distribution
Syntactic Categories
Lexical categories
Noun (N)
John, girl, bravery
Verb (V)
leave, freeze, remain
Adjective (A)
good, tall, old
Preposition (P)
on, in, at
Adverb (Adv)
slowly, silently, now
 Non-lexical categories
Determiner (Det)
the, a, this
Degree word (Deg)
too, so, very
Qualifier (Qual)
perhaps, never, almost
Auxiliary (Aux)
will, can, may
Conjunction (Con)
and, or, but
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Determining a Word’s Category
Some items can belong to more than one
category:
I didn’t get much sleep (N) last night.
I couldn’t sleep (V) because of the noise.
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The child stood near (P) the fence.
The runners will near (V) the finish line.
The end is so near (A).
 What determines a word’s category?
Meaning
One criterion that helps determine a word’s category is the meaning
it denotes.
Nouns name entities such as individuals (Ali, John) and objects (pen,
book).
Verbs designate actions (run, speak), sensations (feel, hurt), and
states (be, remain).
Adjectives designate a property or attribute of an entity.
Adverbs denote properties and attributes of actions, sensations, and
states.
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However, the association between meaning and word category is
not always clear-cut:
Do abstract nouns (truth, friendship) name entities?
Are all action-naming words (ride, push) verbs?
Inflection
Compatibility with certain types of inflections is another
criterion.
Noun
plural –s
Verb
past tense -ed
progressive -ing
Adjective
comparative -er
superlative -est
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However, inflection does not always provide the
information needed to determine a word’s category:
some adjectives are not inflected with the -er or -est
suffixes and some nouns do not take the -s plural suffix.
Distribution
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A word’s distribution, the type of elements
with which it can occur, will help
determine its category.
Noun
Verb
Adjective
determiner
auxiliary
degree word
(a car, the boy)
(has gone, will stay)
(very poor, too small)
(cf. *the speak, *will speech)
Phrase
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Sentences are not strings of words.
Sentences have a hierarchical design.
In this hierarchy, words are grouped
together into larger structural unit.
These syntactic units, built around Nouns,
Verbs, Adjectives, and Prepositions, are
called phrases.
Heads
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Phrases are built around a two-level skeleton.
The lowest level is reserved for the word around
which the phrase is built.
This element is called the head.
NP
VP
AP
PP
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N
V
A
P
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books
eat
certain
in
Specifiers
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Phrases can contain other elements
besides the head.
These elements, called specifiers, have
special semantic and syntactic roles.
[NP the books]
[VP never eat]
[AP quite certain]
[PP almost in]
Specifiers
Semantically, specifiers help make more precise the
meaning of the head:
[NP the book]
specific entity (book)
[VP never eat]
non-occurring event (eating)
[AP quite certain]
to which extent a property (certain) is manifested
[PP almost in]
to which extent a relation (in) is manifested
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Specifiers
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Syntactically, specifiers mark a phrase
boundary (the left boundary in English):
NP
/\
Det N
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the book
VP
/\
Qual V
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never eat
AP
PP
/\
/\
Deg A
Deg P
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|
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quite certain almost in
Specifiers
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The syntactic category of a specifier
differs depending on the syntactic
category of the head:
Category
Typical function
Determiner (Det)
Qualifier (Qual)
Degree word (Deg)
specifier of N
specifier of V
specifier of A or P
Complements
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Phrases can be more complex.
In addition to specifier and head, phrases may
contain a complement.
Complements are phrases themselves.
The existence of their heads is implied by the
meaning of the head in the main phrase:
[NP the books  about something]
[VP never eat  something]
[AP quite certain  about something]
[PP almost in  something]
Complements
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Complements are attached to the right of the
head in English:
VP
NP
Qual
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never
V
|
eat
Det
|
a
N
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hamburger
Tests for Phrase Structure
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How do linguists determine which words
should be grouped together in phrases?
The existence of phrases as constituents
can be independently verified with the
help of special tests:
the substitution test
the movement test
the coordination test
Substitution Test
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Phrases are considered to be syntactic units as they can often be
replaced by an element:
[NP The students] decided to take the course when they read the
syllabus.
(they = the students)
The students will [VP wear ties] if the teachers will do so.
(do so = wear ties)
They stopped [PP at the corner] and we stopped there too.
(there = at the corner)
Movement Test
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A phrase forms a constituent because it can be
moved as a single unit to a different position
within the sentence:
They stopped [PP at the corner]
[PP At the corner], they stopped.
*At they stopped the corner.
Coordination Test
A group of words form a constituent if it
can be joined to another group of words
by a conjunction:
The children [VP read the story]
and
[VP learned a lesson]
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Phrase Structure Rules
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The grammar must ensure that specifiers, heads, and complements occupy
the appropriate positions in phrase structure.
This is regulated by a grammatical mechanism called a phrase structure
rule.
General format: XP 
Examples:
NP 
VP 
AP 
PP 
(Specifier)
X
(Complement) …
(Det)
(Qual)
(Deg)
(Deg)
N
V
A
P
(PP) …
(NP) …
(PP) …
(NP) …
Dots indicate that other complement options are available.
Parentheses indicate that specifiers and complements are optional.
Phrase Patterns
X
/|\
X
/\
S H C
H
C
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| |
always drink water on campus
X
/\
S
X
|
H
H
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|
the man
arrived
X’ Categories
Complements and Heads are attached to a
level between the word and the phrase.
 This intermediate level of structure is
represented by the symbol X’ (X-bar).
 Thus, all phrases have a tri-level structure:
head + complement form X’-level constituent
specifier + X’ constituent form XP
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X’ Categories
XP
X’
Specifier
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X
Head
Why X’ Categories ?
Complement
The Existence of X’
The same phrase structure tests can verify the existence
of X’ categories.
That [N’ book about linguistics] is more informative than the
one you’re reading.
That one is more informative than the one you’re reading.
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Thus,
a.
XP
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(Specifier) X’
b.
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X (Complement)
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X’
Sentences
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The sentence (S) is the largest unit of syntactic analysis.
Sentences are the product of the rule:
S  NP VP
S
NP
VP
NP
Det
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N
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A
scientist
V
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Det
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discovered the
N
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answer
Sentences and XP Rules
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A sentence is not special.
It has internal structure, with a head, a complement,
and a specifier.
The head is an abstract category called Infl, short for
inflection, which indicates the sentence tense (past or
non-past).
Infl, like other constituent heads, is obligatory.
This accounts for the fact that, in English, all sentences
have tense.
Infl takes a VP as its complement.
Infl takes an NP as its specifier.
Therefore, sentences are consistent with the XP rules.
Sentences and XP Rules
InflP (=S)
NP
VP
Infl
Det
A
N
scientist
Pst
NP
V
Det
discovered the
N
answer
Sentences and XP Rules
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Auxiliary verbs are inherently associated
with a particular tense.
Examples like will, can, and may are
necessarily non-past:
*He will/can/may work yesterday.
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Therefore, auxiliary verbs should be
treated as instances of the Infl category.
Sentences and XP Rules
InflP (=S)
NP
VP
Infl
Det
A
N
scientist
NP
V
will discover
Det
N
the
answer
Summing up
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Syntax is concerned with the study of sentence
structure.
Words can be grouped together into a small number of
syntactic categories.
There are some criteria to help determine a word’s
category.
Sentences have a hierarchical design of phrases.
The existence of phrases as constituents can be
independently verified with the help of special tests.
Phrases and sentences have internal structure, with a
head, a complement, and a specifier.
Next Week
Test
Good luck