Transcript Lecture slides - CSE, IIT Bombay

Lexicon
(An Interacting Subsystem in UG)
Part-II
Rajat Kumar Mohanty
Email: [email protected]
IIT Bombay
November 16, 2004
Levels of Representation in UG
Lexicon
D-Structure
Move -alpha
S-Structure
PF
(phonetic form)
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LF
(logical form)
Lexicon
Overgeneration
 Subcategorization Restriction
 Selectional Restriction
 Lexicon and Syntax
 Lexical Derivation

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Overgeneration

Ungrammaticality
 The
boy relied on the girl.
 * The boy relied the girl.
 *The boy relied.

Grammatically Sound but Semantically
Odd
 *The
boy frightens sincerity.
 *Sincerity kicked the boy.
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Overgeneration

PS Rules for the given sentences
S  NP VP
VP V (NP) (PP)
NP Det N
V  rely
Det  the
N boy, girl
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Subcategorization Frames



Specify the categorial class of the lexical item
Specify the environment
Examples
kick:
[V; _ NP]
cry: [V; _ ]
rely: [V; _PP]
put: [V; _ NP PP]
think: : [V; _ S` ]
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Subcategorization Rules


Make a specific lexical item sensitive to the
subcategorization properties of the lexical item
Select a frame depending upon the
subcategorization properties of the verb
Subcategorization Rule:
V
y
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{
/
_NP]
_]
_PP]
_NP PP]
_S`]
}
Subcategorization Rules

The boy relied on the girl.
1. S  NP VP
2. VP  V (NP) (PP) (S`)…
3. NP  Det N
4. V  rely / _PP]
5. P  on / _NP]
6. Det  the
7. N  boy, girl
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Selectional Restrictions

Selectional Rules

A selectional rule specifies certain selectional
restrictions associated with a verb (presumably other
categories: N, A, P).
V
V
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y /
frighten /
{
[+/-ABSTARCT] __
__ [+/-ANIMATE]
[+/-ABSTARCT] __
{ __
[+ANIMATE]
}
}
Lexical Insertion Rule (LIR)

Insert lexical item X under terminal node Y,
where Y corresponds to the categorial
properties of X, and YP corresponds to the
subcategorization properties of X.
YP (verb phrase)
Y
|
X (verb: compose)
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NP
LIR Conditions

LIR performs the operation of inserting lexical
items under terminal nodes subject to two
conditions:
The terminal node must match the categorial class
of the lexical item.
 The phrase containing the terminal node must
match the subcategorization properties of the lexical
item.

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LIR Conditions



rely: [V; __PP]
believe: [V; __S`]
hit: [V; __NP]
VP2
VP1
V
rely
*believe
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PP
V
believe
*rely
VP3
S`
V
hit
*rely
*believe
NP
Lexical Derivation

Whether derivationally related categories such as
translate and translation have separate lexical
entries?

Option

There is one lexical entry for the base form and the
complex N is derived from it by a productive rule.
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Lexical Derivation

Consider the following examples
Translate + ion  translation
 Select + ive  selective
 Computer + ize  computerize
 Elevate + or  elevator
 Correct + ness  correctness
 Correct + ly  correctly

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Lexical Derivation

Lexical derivation affects
Categorial properties of the lexical item
 Subcategorization properties of the lexical item


Examples

John translated the book.


Translate: [V; __NP]
The translation of the book

Translation: [N; __(PP)]
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Lexical Derivation



Lexical derivation rules must apply at a stage
prior to LIR.
The stage at which lexical derivation rules apply
is the lexicon (not merely a list of lexical
entries).
Syntactic component does not include lexical
derivation that affect the categorial and
subcategorization properties of lexical items.
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Lexical Derivation

Affixes are part of the lexicon with categorial
and subcategorization information.
-ion:
-ize:
[N; V_]
[V; N_]
[N]
-hood: [N; [A]
{ }
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__ ]
Lexical Derivation
N
V
create
N
N
-ion
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N
-ion
V
A
V
select
V
select
A
-ive
N
computer
V
-ize
Righthand Head Rule

Righthand Head Rule (RHR) for English
complex categories
 The head of a complex word is its right most
morpheme.
A
N
V
select
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A
N
-ion
-al
Types of Subcategorization

Subcategorization by affixes targets lexical
categories (viz., V, N, A, etc.) to create a complex
terminal category.

Subcategorization by lexical categories targets
phrasal categories (viz., VP, NP, AP, etc.) to create
a syntactic phrase.
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Types of Subcategorization

Subcategorization

Morphological
(relevant to the rules which form complex terminal
categories in the lexicon)

Syntactic
(relevant to the rules of Syntax)
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Types of Affixes

Derivational (under rules of Morphology)
V
N
computer

V
-ize
Inflectional (under rules of Syntax)
N[pl]
N
computer
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V[past]
-s [pl]
V
computerize
-ed [past]
Exercises
1. Workout the subcategorization frame of each
of the lexical items: aspire, declare, conduct, aware,
transport, arrange, deliver, silent
2. Write the selectional rules for the following
verbs: cry, rely, put, think, abandon, aspire
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Exercises
3. Consider the following examples
John believes that Mary left early.
 *John believes if Mary left early.
 *John wonders that Mary left early.
 John wonders if Mary left early.

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Exercises
4. Suggest a formal way of encoding the property
of the verbs believe and wonder .

Tips:
Workout the subcategorization frame
 Write the subcategorization rules
 Assign selectional restrictions

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Exercises
5. Say if the following examples are ungrammatical
violating the subcategorization requirements of
the lexical items.
This problem, I can solve.
 I can solve.
 I can solve this problem.
 He comes from London.
 He comes from.
 We need someone to generate on new ideas.

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Exercises
6. Assign a tree structure to each of the complex
categories listed below.










Musical
Establishment
Modernization
Interpretations
Colonized
Unhappiness
Stupidity
Formal
Fixable
organic
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Exercises
7. Assign a tree structure to each of the
compounds listed below.
Crybaby
 Bankroll
 Overestimate
 Dryclean
 Drycleaner
 Bluebottle

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Exercises
8. State the categorial and subcategorization
properties of each of the suffixes listed below.
-er
 -ize
 -or
 -ly
 -al
 -ness
 -ity

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Exercises
9. Find out the simple lexical items and the
complex terminal categories from the given list.








Formality
officially
Table
Tree
Specified
Single
Useful
exactly
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Exercises
10. Look at the tree and state the categorial and
subcategorization properties of the affixes.
N
V
N
de-
V
A
N
nation
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16, 2004
-tion
V
A
-al
-ize
Sources and further reading



Comsky, Noam. 1965. Aspects of the Theory of
Syntax. CUP, Cambridge.
Comsky, Noam. 1981. Lectures on Government
and Binding. Foris, Dordrecht.
Ouhalla, Jamal. 1994. Introducing Transformational
grammar. Arnold, London.
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THANK YOU
November 16, 2004