Lexicon (An Interacting Subsystem in UG) Part-I

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

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

3. The Theory of UG • Two conditions • Compatible with the diversity of existing grammars • Sufficiently constrained and restricted • Central Concept • grammar not language. • Language: derivative at a higher level of abstraction from actual neural mechanism.

4. Interacting subsystems • UG consists of interacting subsystems • Various subcomponents of the rule system of grammar • Subsystems of Principles

5. Subcomponents • Subcomponents of the rule system • Lexicon • Syntax • Categorial component • Transformational component • PF-component • LF-component

6. Principles • Subsystem of Principles • X-bar Theory • Bounding Theory • Government Theory • Theta-theory • Binding Theory • Case Theory • Control Theory

7. Lexicon • Overgeneration • Subcategorization Restriction • Selectional Restriction • Separating the Lexicon from Syntax • Lexical Derivation

8. 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.

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

10. Subcategorization Restrictions • Subcategorization Frames • Subcategorization Rules

11. 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` ]

12. Subcategorization Frames • The information in the subcategorization frame implies that kick can only be inserted under a V node in a VP structure in which V has an NP sister. • The subcategorization information is associated with the individual lexical items in their lexical entries.

13. Subcategorization Rules • These rules make a specific lexical item sensitive to the subcategorization properties of the lexical item. • Selection of a frame depends on the subcategorization properties of the verb. Subcategorization Rule: { } _NP] _ ] _PP] _NP PP] _S`] V y /

14. 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

15. Context Free and Context Sensitive Rules • Rule (4) ensures the non-generation of • *The boy relied. • *The boy relied the girl. • Rule (4) and (5) are context sensitive rules • Rule (1-3) are context free rules

16. Selectional Restrictions • Necessity of a Mechanism • Can we exclude these two ill-formed structures ? • *The boy frightened sincerity. • *Sincerity kicked the boy. • A system should include a mechanism which ensures that only nouns with appropriate properties are associated with given verbs in a given context

17. Selectional Restrictions • Inherent Properties of Nouns • [+/- ABSTRACT], [+/- ANIMATE] • Like subcategorization properties, they are specified in the lexical entries • Sincerity [+ ABSTRACT] • Boy [+ANIMATE] • Lexical information of this type can be used to set up a context sensitive ‘rewrite rule’

18. 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]

19. Exercises • Workout the subcategorization frame of each of the lexical items: aspire, declare, conduct, aware, transport, arrange, deliver, silent • Write selectional rules for the following verbs: cry, rely, put, think, abandon, aspire

20. Exercises • 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. • 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

21. 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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