Techniques of Grammatical Analysis

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Techniques of Grammatical Analysis

• Rajat Kumar Mohanty
• rkm_at_cse.iitb.ac.in
• IIT Bombay

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What is Grammar?

• A theory of language
• A theory of competence of a native speaker
• An explicit model of competence
• A finite set of rules

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What are the requirements?

• A model of competence
• Should be able to generate an infinite set of
  grammatical sentences of the language
• Should not generate any ungrammatical ones
• Should be able to account for ambiguities
• If two sentences are understood to have same
  meaning, the grammar should give the same
  structure for both at some level
• If two sentences are understood to have different
  internal relationship, the grammar should assign
  different structural description

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Techniques of Grammatical Analysis

• Two main devices
• Breaking up a string
• Sequential
• Hierarchical
• Transformational
• Labeling the constituents
• Morphological
• Categorial
• Functional
• A grammar may combine any of these devices for
  grammatical analysis.

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Breaking up and Labeling

• Sequential Breaking up
• Sequential Breaking up and Morphological labeling
• Sequential Breaking up and Categorial labeling
• Sequential Breaking up and Functional labeling
• Hierarchical Breaking up
• Hierarchical Breaking up and Categorial Labeling
• Hierarchical Breaking up and Functional Labeling

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Sequential Breaking up

• This device breaks up a sentence into a sequence
  of morphemes
• the boy s kill ed the un happy
  rat s
• raam ne dande se saap ko maar aa
• If a sentence is understood in two different
  ways, a grammar should give two corresponding
  descriptions
• They can fish
• They are able to fish
• They put fish in cans

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Sequential Breaking up and Morphological labeling
After breaking up a sentence, we can give
morphological labels to each units
the boy s kill ed the un
happy rat s
word stem affix stem affix
word affix stem stem affix
raam ne dande se saap ko maar aa
word affix word affix
word affix word affix
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Sequential Breaking up and Categorical Labeling

• This boy can solve the problem

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Sequential Breaking up and Categorical Labeling
(continued)

• They can fish
• Pronoun Aux Verb
• They can fish
• Pronoun Verb Noun

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Sequential Breaking up and Categorical Labeling
(continued)

• They called her a taxi
• Pronoun Verb Pronoun Article Noun
• They said she was a taxi
• They called a taxi for her

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Sequential Breaking up and Functional labeling

• They called her a taxi

Subject
Verbal
IO
DO
They called her a taxi
Object Complement
Subject
Verbal
DO
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Sequential Breaking up and Functional labeling
(continued)
Old men and women
Head
modifier
Head
coordinator
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Hierarchical Breaking up

• This device breaks up a sentence into its
  constituents at different hierarchies or levels

Old men and women
Old men and women
men and women
and
women
Old men
Old
women
and
men
men
Old
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Hierarchical Breaking up and Categorial Labeling

• Poor John ran away

ADJ
V
ADV
N
VP
NP
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Hierarchical Breaking up and Functional Labeling

• Immediate Constituent Analysis
• Construction types in terms of the function of
  the constituents
• Predication (subject predicate)
• Modification (modifier head)
• Complementation (verbal complement)
• Subordination (subordinator dependent unit)
• Coordination (independent unit coordinator
  independent unit)

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In the morning, the sky looked much
brighter
Head
Mod

• Mod

Head
Mod
Head
Verbal
Complement
Predicate
Subject
Sub
DU
Head
Modifier
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Hierarchical Breaking up and Categorial
/Functional Labeling

• Hierarchical Breaking up coupled with Categorial
  /Functional Labeling is a very powerful device
• But there are ambiguities which demand something
  more powerful

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Love of God

• Someone loves God
• God loves someone

Love of God
Love of God
Head
Modifier
Noun Phrase
Prepositional Phrase
DU
Sub-
God
of
love
love
of
God
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Generative Grammar

• A generative grammar
• generates all the grammatical sentences of the
  language
• rejects all the ungrammatical ones
• It is free to choose and combine any of the
  techniques of breaking up and labeling
• Depending upon what tools the grammar combines,
  we have different types of grammar

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Types of Generative Grammar

• Finite State Model
• (sequential)
• Phrase Structure Model
• (sequential hierarchical)
• Transformational Model
• (sequential hierarchical transformational)

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Phrase Structure Model

• Inadequacies
• Ambiguity
• Paraphrase Relationship
• Constructional Homonymy

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Ambiguity

• If a sentence is understood to have two meanings,
  a grammar should give two corresponding
  structural descriptions
• PS grammar fails to meet this demand
• The shooting of the hunters
• The hunter shot someone
• Someone shot the hunters

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NP
PP
NP
N
Det
P
NP
Det
N
the
shooting
of
the
hunters
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Paraphrase Relationship

• If two sentences are understood to have the same
  meaning, a grammar should give the same
  structural description for the two sentences at
  some level
• PS grammar fails to meet this demand
• Examples
• The boy slapped the girl
• The girl was slapped by the boy

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S
VP
NP
N
Det
V
NP
Det
N
The
boy
slapped
the
girl
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S
VP
NP
N
Det
V
PP
Aux
V
P
NP
The
girl
slapped
by
boy
was
the
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Constructional Homonymy

• If two sentences are not understood the same way,
  a grammar should give two structural descriptions
• PS grammar cannot do this
• The audience was asked to leave by the side-door
• The audience was asked to leave by the chairman

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S
VP
NP
V
Inf. Phr
N
Det
Aux
V
Inf.
VP
V
PP
P
NP
Det
N
The
audience
asked
to
Side-door
was
leave
by
the
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S
VP
NP
V
Inf. Phr
N
Det
Aux
V
Inf.
VP
V
PP
P
NP
Det
N
The
audience
asked
to
Chairman
was
leave
by
the
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Transformational Model

• If a generative grammar makes use of all the
  three
• -sequential
• -hierarchical and
• -transformational
• is called a Transformational grammar.

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Transformational model

• PS model

• Makes use of PS rules exclusively
• PS rules generate surface structure

• Makes use of PS rules and transformational rules
• PS rules generate DS
• DS is converted into the surface structure by
  transformational rules

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PS grammar
Surface Structure
PS rules

• Transformational grammar

PS rules
Transformation
Deep Structure
Surface Structure
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Why wasnt he punished?

• PS rules
• S ? NP VP
• VP ? V - NP PP
• V ? Aux V
• Aux? (Tense)-(Modal)-(Perf)-(Prog)
• Tense ? pres/past
• NP ? (PreDet) - (Det) - (Ord) -(Quan) -(AP)-N
• Lexical substitution

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S
VP
NP
VG
PP
NP
Aux
V
Tense
Someone
past
him
for some reason
punish
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Why wasnt he punished?(continued)

• Transformations
• Passivization
• Agent deletion
• Negation
• Neg. Contraction
• Wh- substitution
• Interrogation
• Wh- fronting
• Affix switch

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Passivization
S
VP
NP
VG
PP
PP
Aux
V
P
NP
N
Tense
Pass
for Some reason
He
past
by
punish
be
en
someone
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Agent Deletion
S
VP
NP
VG
PP
Aux
V
Tense
Pass
for some reason
He
past
punish
be
en
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Negation
S
VP
NP
VG
PP
Aux
V
Tense
Pass
for some reason
He
past
punish
be
en
not
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Neg. Contraction
S
VP
NP
VG
PP
Aux
V
Tense
Pass
for some reason
He
past
punish
en
benot
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Wh- Substitution
S
VP
NP
VG
WH
Aux
V
Tense
Pass
why
He
past
punish
en
benot
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Interrogative
S
VP
NP
Aux
VG
WH
V
Tense
why
he
past
punish
en
benot
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Wh-fronting
S
VP
NP
Aux
WH
VG
V
Tense
why
he
past
punish
en
benot
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Affix switch
S
VP
NP
Aux
WH
VG
Tense
V
past
benot
punish
en
why
he
wasnot
punished
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Suggested Readings

• Lyons, John. 1977. Chomsky. Fontana, London.
• Palmer, Frank. Grammar
• Crystal, David. Linguistics

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THANK YOU

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