Optimality Theory
Presented by
Ashour Abdulaziz, Eric Dodson,
Jessica Hanson, and Teresa Li
Overview
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Introduction
How to interpret OT
Historical Development
Theory
Application
Pros and Cons
Optimality Theory
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• 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)
Constraints
• Constraints are:
• Universal
• Ranked
• Violable
• In Conflict
In other words…
• Constraints are universal, but crosslinguistic 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.
What's for lunch?
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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
What's for lunch?
/input/
Chit-Chat
Cafe
Yumm
Park Cafe
Kenny &
Zuke's
*Far away Soup
Vegan
Options
*Lunch
Special
What's for lunch?
/input/
*Far away Soup
Chit-Chat
*!
Vegan
Options
*Lunch
Special
*
*
Cafe
Yumm
*
Park Cafe
Kenny &
Zuke's
*!
*!
This is for lunch.
/input/
*Far away Soup
Chit-Chat
*!
Vegan
Options
*Lunch
Special
*
*
Cafe
Yumm
*
Park Cafe
Kenny &
Zuke's
*!
*!
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
Pre-OT History
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Theoretical problem with generative
phonology: Conspiracies
Kisseberth (1970)
Basic example:
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A->B /X_Y
A->C /X_Y
A->⊘ /X_Y
The rules "conspire" against the form XAY
Generative approaches have no explanation
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.
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?
Constraints
• Constraints are:
• Universal
• Ranked
• Violable
• In Conflict
Identifying Constraints
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Little agreement on what constraints exist
Some disagreements (or flexibility) in how
to propose a new constraint
Language Typology
Phonetic motivation
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.
Faithfulness
• Faithfulness: constraints enforce similarity
between input and output
• Fights against change
• Example:
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Ident-IO(Voice)
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Segments in the output have the same
•voicing as those in the input
Functions
• Gen (Generator)
• Eval (Evaluator
Gen
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Underlying forms are input for gen
Gen creates (possibly infinite) list of
candidates
/dogz/
dogz
dogs
doks
dokz
do!s
dugz
togz
gogz
dogəz
dogəs
dogədog
...
Eval
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Applies ranking to candidate list
Selects most harmonic candidate
An example analysis
•[dɑg]
[dɑgz]
•[kæt]
[kæts]
•Assume plural morpheme is /z/
•Explain variation between [z] and [s]
An example analysis
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Identify constraints
Propose some candidates
Propose a ranking
Show alternate ranking
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.
TPR Demo
• Input: /kæ t - z/
•Find the optimal candidate given:
•1. Agree-Voice
•2. Ident-IO (Voice)
•3. *Voiced Word-Final
Demo - Tableau
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
Demo - Tableau
Follow-up: What about the candidate [kaʔz]?
Pros of OT
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Expands to other areas of linguistics
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Unites different processes that are for the
same purposes(conspiracy)
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A->B /X_Y
A->C /X_Y
A->O /X_Y
Eliminates derivation
Criticism of OT
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Existence of constraint not easily defined
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Ambiguity in how constraints are created
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Opacity difficult to explain
"Too many solutions" problem
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Reverse of conspiracy problem
Conclusion
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How to interpret a Tableaux
History and Reasons for Development
Theory
Application
Pros and Cons
Further Resources
• Kager, Rene (1999). Optimality Theory.
Cambridge, UK: Cambridge University
Press.
• OT Archive at Rutgers: http://roa.rutgers.edu/