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Optimality Theory

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Title: Optimality Theory


1
Optimality Theory
  • Presented by
  • Ashour Abdulaziz, Eric Dodson, Jessica Hanson,
    and Teresa Li

2
Overview
  • Introduction
  • How to interpret OT
  • Historical Development
  • Theory
  • Application
  • Pros and Cons

3
Optimality Theory
  • Central Idea Surface Forms of language reflect
    resolutions of conflicts between competing
    demands or constraints.
  • Language is a system of conflicting forces.
  • The scope of OT is to explain a wide range of
    linguistic phenomena (including syntax)

4
Constraints
  • Constraints are
  • Universal
  • Ranked
  • Violable
  • In Conflict

5
In other words
  • Constraints are universal, but cross-linguistic
    differences are accounted for by differences in
    ranking.
  • All surface forms violate at least some
    constraints.
  • The optimal surface form will have the least
    serious violations of the ranked set of
    constraints for a language.

6
What's for lunch?
  • Jessica doesn't want to go far
  • Eric wants a place that has a lunch special
  • Ashour wants a place that has soup
  • Teresa is trying to be vegan
  • Options Chit-chat, Cafe Yumm, Park Cafe, Kenny
    Zuke's

7
What's for lunch?
/input/ Far away Soup Vegan Options Lunch Special
Chit-Chat
Cafe Yumm
Park Cafe
Kenny Zuke's
8
What's for lunch?
/input/ Far away Soup Vegan Options Lunch Special
Chit-Chat !
Cafe Yumm
Park Cafe !
Kenny Zuke's !
9
This is for lunch.
/input/ Far away Soup Vegan Options Lunch Special
Chit-Chat !
Cafe Yumm
Park Cafe !
Kenny Zuke's !
10
Optimality Theory - History
  • It is a linguistic model proposing that the
    observed forms of language arise from the
    interaction between conflicting constraints.
  • OT models grammars as systems that provide
    mappings from inputs to outputs the inputs are
    conceived of as underlying representations and
    the outputs as their surface realizations

11
Pre-OT History
  • Theoretical problem with generative phonology
    Conspiracies
  • Kisseberth (1970)
  • Basic example
  • A-gtB /X_Y
  • A-gtC /X_Y
  • A-gt? /X_Y
  • The rules "conspire" against the form XAY
  • Generative approaches have no explanation

12
Optimality Theory - History
  • Prince and Smolensky (1993) introduced the
    Optimality Theory (OT), as a framework for
    Linguistic analysis,
  • Kager (1999) gave an introduction to the theory.
  • The theory was later expanded by Prince and John
    McCarthy in (2001)
  • Optimality theory is usually considered a
    development of generative grammar.

13
The fundamentals of OT
  • How OT addresses the following questions-
  • (1) How are the constraints on the output of the
    grammar satisfied? What is the relationship
    between constraints on output structures and the
    operations that transform input into outputs? How
    are the triggering and blocking effects accounted
    for?
  • (2) What is the relationship between the
    universal and the language particular? How can
    constraints differ in their activity from
    language to language?

14
Constraints
  • Constraints are
  • Universal
  • Ranked
  • Violable
  • In Conflict

15
Identifying Constraints
  • Little agreement on what constraints exist
  • Some disagreements (or flexibility) in how to
    propose a new constraint
  • Language Typology
  • Phonetic motivation

16
Markedness
  • Markedness enforce well-formedness of the output
  • Unmarked "preferred"
  • Marked "avoided"
  • "Fights" against input that is marked
  • Example
  • Voiced Word-Final Obstruent
  • Word-final obstruents must not be voiced.

17
Faithfulness
  • Faithfulness constraints enforce similarity
    between input and output
  • Fights against change
  • Example
  • Ident-IO(Voice)
  • Segments in the output have the same
  • voicing as those in the input

18
Functions
  • Gen (Generator)
  • Eval (Evaluator

19
Gen
  • Underlying forms are input for gen
  • Gen creates (possibly infinite) list of
    candidates

dogz togz dogs gogz doks dog?z dokz dog?s do!s
dog?dog dugz ...
/dogz/
20
Eval
  • Applies ranking to candidate list
  • Selects most harmonic candidate

21
An example analysis
  • d?g d?gz
  • kæt kæts
  • Assume plural morpheme is /z/
  • Explain variation between z and s

22
An example analysis
  • Identify constraints
  • Propose some candidates
  • Propose a ranking
  • Show alternate ranking

23
Proposed Constraints
  • Agree-Voice - "Obstruent voicing agreement"
  • Markedness constraint contiguous obstruents
    must agree in voicing
  • Ident-IO (Voice) - "Voicing Faithfulness"
  • Faithfulness constraint output segment voicing
    must be the same as input
  • Voiced Word-Final Obstruent - "No word-final
    voicing"
  • Markedness constraint word-final obstruents
    must not be voiced.

24
TPR Demo
  • Input /kæ t - z/
  • Find the optimal candidate given
  • 1. Agree-Voice
  • 2. Ident-IO (Voice)
  • 3. Voiced Word-Final

25
Demo - Tableau
26
TPR Demo - Wrong Ranking
  • What happens with the wrong ranking?
  • Input /kæ t - z/
  • Wrong ranking
  • 1. Ident-IO (Voice)
  • 2. Agree-Voice
  • 3. Voiced Word-Final

27
Demo - Tableau
Follow-up What about the candidate ka?z?
28
Pros of OT
  • Expands to other areas of linguistics
  • Unites different processes that are for the same
    purposes(conspiracy)
  • A-gtB /X_Y
  • A-gtC /X_Y
  • A-gtO /X_Y
  • Eliminates derivation

29
Criticism of OT
  • Existence of constraint not easily defined
  • Ambiguity in how constraints are created
  • Opacity difficult to explain
  • "Too many solutions" problem
  • Reverse of conspiracy problem

30
Conclusion
  • How to interpret a Tableaux
  • History and Reasons for Development
  • Theory
  • Application
  • Pros and Cons

31
Further Resources
  • Kager, Rene (1999). Optimality Theory.
    Cambridge, UK Cambridge University Press.
  • OT Archive at Rutgers http//roa.rutgers.edu/

32
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