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Lexicon (An Interacting Subsystem in UG) Part-II

Lexicon (An Interacting Subsystem in UG) Part-II. Rajat Kumar Mohanty Email: rkm@cse.iitb.ac.in IIT Bombay. Levels of Representation in UG. Lexicon. D-Structure. Move - alpha. S-Structure. LF (logical form). PF (phonetic form). Lexicon. Overgeneration

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Lexicon (An Interacting Subsystem in UG) Part-II

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  1. Lexicon(An Interacting Subsystem in UG)Part-II Rajat Kumar Mohanty Email: rkm@cse.iitb.ac.in IIT Bombay

  2. Levels of Representation in UG Lexicon D-Structure Move -alpha S-Structure LF (logical form) PF (phonetic form)

  3. Lexicon • Overgeneration • Subcategorization Restriction • Selectional Restriction • Lexicon and Syntax • Lexical Derivation

  4. 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.

  5. Overgeneration • PS Rules for the given sentences S  NP VP VP V (NP) (PP) NP Det N V  rely Det  the N boy, girl

  6. 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` ]

  7. 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 /

  8. 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

  9. 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]

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. Lexical Derivation • Consider the following examples • Translate + ion  translation • Select + ive  selective • Computer + ize  computerize • Elevate + or  elevator • Correct + ness  correctness • Correct + ly  correctly

  15. 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)]

  16. 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.

  17. Lexical Derivation • Affixes are part of the lexicon with categorial and subcategorization information. -ion: [N; V_] -ize: [V; N_] { } [N] __ ] [N; -hood: [A]

  18. Lexical Derivation N N V N V N select create -ion -ion V A N V V A computer -ize select -ive

  19. 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

  20. 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.

  21. Types of Subcategorization • Subcategorization • Morphological (relevant to the rules which form complex terminal categories in the lexicon) • Syntactic (relevant to the rules of Syntax)

  22. Types of Affixes • Derivational (under rules of Morphology) • Inflectional (under rules of Syntax) V N V computer -ize N[pl] V[past] N -s [pl] V -ed [past] computer computerize

  23. 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

  24. 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.

  25. 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

  26. 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.

  27. Exercises 6. Assign a tree structure to each of the complex categories listed below. • Musical • Establishment • Modernization • Interpretations • Colonized • Unhappiness • Stupidity • Formal • Fixable • organic

  28. Exercises 7. Assign a tree structure to each of the compounds listed below. • Crybaby • Bankroll • Overestimate • Dryclean • Drycleaner • Bluebottle

  29. Exercises 8. State the categorial and subcategorization properties of each of the suffixes listed below. • -er • -ize • -or • -ly • -al • -ness • -ity

  30. 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

  31. Exercises 10. Look at the tree and state the categorial and subcategorization properties of the affixes. N V N de- V -tion A V N A -ize nation -al

  32. 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.

  33. THANK YOU

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