Optimality Theory

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Optimality Theory

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

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Overview

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

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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)

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Constraints

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

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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.

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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

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What's for lunch?
/input/ Far away Soup Vegan Options Lunch Special
Chit-Chat
Cafe Yumm
Park Cafe
Kenny Zuke's
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What's for lunch?
/input/ Far away Soup Vegan Options Lunch Special
Chit-Chat !
Cafe Yumm
Park Cafe !
Kenny Zuke's !
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This is for lunch.
/input/ Far away Soup Vegan Options Lunch Special
Chit-Chat !
Cafe Yumm
Park Cafe !
Kenny Zuke's !
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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

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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

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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.

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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?

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Constraints

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

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Identifying Constraints

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

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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.

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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

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Functions

• Gen (Generator)
• Eval (Evaluator

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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/
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Eval

• Applies ranking to candidate list
• Selects most harmonic candidate

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An example analysis

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

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An example analysis

• Identify constraints
• Propose some candidates
• Propose a ranking
• Show alternate ranking

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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.

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TPR Demo

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

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Demo - Tableau
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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

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Demo - Tableau
Follow-up What about the candidate ka?z?
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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

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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

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Conclusion

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

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Further Resources

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

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