THETA THEORYTHETA THEORYPresenter:Presenter:

Nguyễn Thị Hoàn Nguyễn Thị Hoàn

1. Definition Theta Theory, or Thematic Theory (θ-theory) is the module that deals with the valency requirements of verbs. It incorporates a set of participant roles, called Theta Roles. Their distribution in sentence structure is mediated chiefly by the Projection Principle and the Theta-Criterion. (A Dictionary of Grammatical Terms in Linguistics)

Types of Theta RolesTypes of Theta Roles

A Theta Role represents the semantic relationship of arguments with the predicate .

Type Definition ExampleAgent It is the initiator or the doer of the action.

Also it should be alive and able to take conscious decisions; it is mostly subject of a clause

“Sarah finished the work”

Experiencer It is the argument that feels or perceives events; it might also be experiencing some psychological state.

“John was happy”

Theme/Patient

It is an entity that undergoes actions, is moved, experienced, or perceived; it is also called “patient”

“John killed the bird”

Goal The entity towards which something moves.

“She goes to the library”

Recipient It occurs only with verbs denoting change of possession.

-“Peter got a book from her”.

Source It is the unit from which the action takes place

“He returned from Taza”.

Type Definition ExampleLocation It is the place in which the action

occurs or in which a theme is located.

“In the seminar, we discussed the topics”.

Instrument It is a means by which something comes about.

“John killed Mary with a gun”.

Benificative It is the one who is given some help or to whose best something happens

“He bought some flowers for his wife”.

Possessor It is the one who has or owns something.

“John has a big car”.

Percept It is someone or something that is perceived.

“John smelled funny”.

The Theta-Criterion &The Theta-Criterion & The Projection Principle The Projection Principle

Theta Theory operates at D-structure through the assignment of θ-roles to arguments. This theory is based on two fundamental principles, namely the Theta-Criterion and the Projection Principle.

The Theta-CriterionThe Theta-Criterion

Definition:

Each argument bears one and only one θ- role, and each θ-role is assigned to one and only one argument.( Chomsky (1981)

ExamplesExamples

Example 1: look back the table

(a) John killed the bird.

- [John] is assigned the Theta- role “agent”

- [the bird] is assigned the θ-role “patient”.

ExamplesExamplesExample 2:(b) The navy sank the enemy ship by

a torpedo.

Both [the navy] and [by a torpedo] bear the same theta role ‘agent’

The sentence is considered to be ungrammatical

Replace "by" with "with"

The Projection PrincipleThe Projection Principle Definition

Representations at each syntactic level must be projected from the lexicon, in that they observe the Subcategorization properties of lexical items. Chomsky (1981)

Help us to judge the grammaticality of some syntactic structures

DefinitionDefinition

According to the generalized Projection Principle, a verb that takes an agent subject cannot take a theme or a goal subject, while verbs that have a non-thematic subject cannot be inserted in a structure where its subject has received a θ-role.

ExamplesExamples(2a) John murdered Mary.

(2b) It seems to be a day of troubles- In (2a), “John” is assigned the θ-role

‘agent’ and “to murder” cannot take a theme subject

- In (2b), the verb “seem” has a non-thematic subject and therefore cannot take a thematic subject.

ValencyValency

(linguistics) the number of grammatical elements that a word, especially a verb, combines with in a sentence

LexiconLexicon

All the words and phrases used in a particular language or subject; all the words and phrases used and known by a particular person or group of people.