Lexicon An Interacting Subsystem in UG PartII

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Lexicon(An Interacting Subsystem in UG)Part-II

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

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Levels of Representation in UG

• Lexicon

D-Structure
Move -alpha
S-Structure
LF (logical form)
PF (phonetic form)
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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


_NP _ _PP _NP PP _S
V
y
/
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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).

__


/-ABSTARCT
V
y
/
/-ANIMATE
__


__
V
/-ABSTARCT
frighten
/
__
ANIMATE
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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)
NP
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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
VP3
VP1
V
S
V
NP
V
PP
believe
hit
rely
rely
rely
believe
believe
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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 N V_
• -ize V N_

N
__
N
-hood
A
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Lexical Derivation
N
N
V
N
V
N
select
create
-ion
-ion
V
A
N
V
V
A
computer
-ize
select
-ive
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Righthand Head Rule

• Righthand Head Rule (RHR) for English complex
  categories
• The head of a complex word is its right most
  morpheme.

A
N
A
V
N
-al
select
-ion
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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)
• Inflectional (under rules of Syntax)

V
N
V
computer
-ize
Npl
Vpast
N
V
-ed past
-s pl
computer
computerize
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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
N
V
de-
V
-tion
V
A
N
A
-ize
nation
-al
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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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