Techniques of Grammatical Analysis Rajat Kumar Mohanty rkm@cse.iitb.ac.in IIT Bombay

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

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

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.

Breaking up Labeling Morphological Categorial Functional Grammatical Analysis Techniques Sequential Hierarchical Transformational Morphological Categorial Functional

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

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

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

Sequential Breaking up and Categorical Labeling This boy can solve the problem This boy can solve the problem Det N Aux V Det N S

Sequential Breaking up and Categorical Labeling (…continued) They can fish Pronoun Aux Verb They can fish Pronoun Verb Noun

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

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

Sequential Breaking up and Functional labeling (…continued) Old men and women modifier Head coordinator Head

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 Old men and women Old men and women Old men

Hierarchical Breaking up and Categorial Labeling Poor John ran away ADJ N V ADV NP VP

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)

In the morning, the sky looked much brighter Mod Head Mod Head Mod Head Verbal Complement Subject Predicate Sub DU Head Modifier

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

Love of God Love of God Love of God Someone loves God God loves someone Love of God Love of God Head Modifier Noun Phrase Prepositional Phrase Sub- DU love of God love of God

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

Types of Generative Grammar Finite State Model (sequential) Phrase Structure Model (sequential + hierarchical) Transformational Model (sequential + hierarchical + transformational)

Phrase Structure Model Inadequacies Ambiguity Paraphrase Relationship Constructional Homonymy

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

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

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

S VP NP Det N V NP Det N The boy slapped the girl

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

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

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

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

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

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

PS grammar Surface Structure PS rules Transformational grammar PS rules Transformation Deep Structure Surface Structure

Why wasn’t 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

S VP NP VG NP PP Aux V Tense Someone past punish him for some reason

Why wasn’t he punished? (…continued) Transformations Passivization Agent deletion Negation Neg. Contraction Wh- substitution Interrogation Wh- fronting Affix switch

Passivization S VP NP VG PP PP Aux V P NP N Tense Pass for Some reason He past be en punish by someone

Agent Deletion S VP NP VG PP Aux V Tense Pass for some reason He past be en punish

Negation S VP NP VG PP Aux V Tense Pass for some reason He past be not en punish

Neg. Contraction S VP NP VG PP Aux V Tense Pass for some reason He past be’not en punish

Wh- Substitution S VP NP VG WH Aux V Tense Pass why He past be’not en punish

Interrogative S VP Aux NP VG WH V Tense why past be’not he en punish

Wh-fronting S VP WH Aux NP VG V Tense why past be’not he en punish

Affix switch S VP WH Aux NP VG Tense V be’not past punish en why was’not he punished

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

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