Optimality Theory

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# Optimality Theory - PowerPoint PPT Presentation

Optimality Theory. Presented by Ashour Abdulaziz, Eric Dodson, Jessica Hanson, and Teresa Li. Overview. Introduction How to interpret OT Historical Development Theory Application Pros and Cons. Optimality Theory.

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## Optimality Theory

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Presentation Transcript
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?

8. What's for lunch?

9. This is for lunch.

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->B /X_Y • A->C /X_Y • A->⊘ /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 dogəz dokz dogəs do!s dogədog dugz ... /dogz/

20. Eval • Applies ranking to candidate list • Selects most harmonic candidate

21. An example analysis • [dɑg] [dɑgz] • [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 [kaʔz]?

28. Pros of OT • Expands to other areas of linguistics • Unites different processes that are for the same purposes(conspiracy) • A->B /X_Y • A->C /X_Y • A->O /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/