Optimality theory
Optimality theory or OT is a linguistic model proposed by the linguists Alan Prince and Paul Smolensky in 1993, and expanded by John J. McCarthy and Alan Prince in 1993. Although a lot of the interest in OT has been associated with its use in phonology (the area to which OT was first applied), the theory is also applicable to other subfields of linguistics (e.g. syntax, where it has been combined with lexical functional grammar; semantics). Optimality theory is usually considered a development of generative grammar, which shares its focus on the investigation of universal principles, linguistic typology and language acquisition. There are, however, linguists who consider OT to be an entirely new theory of grammar. Specifically, they reject the idea of universal grammar.
OT is often called a connectionist theory of language, because it has its roots in neural network research, though the relationship is now largely of historical interest. It arose in part as a successor to the theory of harmonic grammar, developed in 1990 by Géraldine Legendre, Yoshiro Miyata and Paul Smolensky.
The main idea of OT is that the observed, "surface", forms of the language arise from the resolution of conflicts between grammatical constraints. These constraints are minimally violated in that the form that surfaces is the one which incurs the least serious violations, compared to a set of possible candidates. The seriousness of a violation is defined in terms of hierarchies of constraints in which the violations of higher-ranked constraints are most serious. This domination is said to be strict in that higher constraints take absolute priority over lower constraints. That is, given a constraint C1, ranked above C2 and C3, the expression of the language that surfaces (the winning candidate) may perform worse than its competitors in both C2 and C3, as long as it performs better in C1. Constraints are generally regarded as universal (though not by all OT researchers), but their ranking is particular to each language, accommodating for language variation. Acquisition of a language can be roughly described as the process of adjusting the ranking of these constraints to match the language one is learning.
Constraints can be grouped into two main types: faithfulness constraints and markedness constraints. A faithfulness constraint requires that the observed surface form (the output) must match the input form in some particular way. The input form is a hypothetical object that is typically generated by some simple rule. A markedness constraint imposes some requirement on the form. Consider the manifestation of the English plural morpheme as a simplified example.
Consider two examples: cat + s → cats and class + s → classes. In the cat case, the form cats
passes all the markedness constraints: it is a well-formed word that is pronouncible.
Thus, the faithfulness constraint wins, and the output is cats.
In the case of class+s, there is a markedness constraint that
prohibits the classs form (presumably one cannot have two /s/ sounds in succession in English). The markedness constraint is assumed to be
ranked higher, so the faithfulness constraint is over-ridden.
Other rules operate, and one ends up with classes.
Sometimes a language may appear to lack the effects of a constraint. Since constraints are thought to be universally present, the language would still be thought as having the constraint active, but in a lower ranking, masked by the effects of higher ranked constraints. Thus it would be expected that sometimes lower constraints may demonstrate some effects under very specific conditions (where all higher constraints are satisfied) even in languages where this is not usually observable. These are cases known as ‘the emergence of the unmarked’. For instance, English speaking Optimality Theorists
refer to tables of constraints as "tableaux", which is perhaps an emergence
of certain constraints important in French that would otherwise be ranked below most
English phonotactic constraints.
Optimality Theory makes the claim that all phonological interactions can be analyzed as the interaction of faithfulness and markedness. No phonological process should be found in which an optimal candidate has worse faithfulness violations without having better markedness violations than a competing candidate. Many linguists believe that this is a falsifiable prediction, in the sense of Karl Popper and that Optimality Theory is thus a scientific theory. For instance, Idsardi (2000) has argued that OT has been disproved by violations of the above claim relating to phonological opacity. Others, like Sanders (2003) and Green (2005), have countered that all cases of opacity brought forward to date are influenced by the morphology of the language in question and that only purely phonological opacity would disprove OT. A current limitation of OT is that different workers in the field use different sets of constraints and assumptions; OT is thus best thought of as a means of representing language, a paradigm in the sense of Thomas Samuel Kuhn rather than a theory.
References
- Blutner, Reinhard, Helen de Hoop and Petra Hendriks (2004). Optimal Communication. Book draft, University of Amsterdam/Radboud University Nijmegen/University of Groningen.
- Dresher, Bezalel Elan (1996): The Rise of Optimality Theory in First Century Palestine. GLOT International 2, 1/2, January/February 1996, page 8 (a humorous introduction for novices)
- Green, Antony D. (2005). Phonology limited. Ms., University of Potsdam. ROA-745-0605, Rutgers Optimality Archive.
- Kager, René (1999). Optimality Theory. Cambridge: Cambridge University Press.
- Idsardi, William J. (2000). Clarifying opacity. The Linguistic Review 17:377-50.
- Legendre, Géraldine, Jane Grimshaw and Sten Vikner. Optimality-theoretic syntax. MIT Press.
- McCarthy, John (2001). A Thematic Guide to Optimality Theory. Cambridge: Cambridge University Press.
- McCarthy, John and Alan Prince (1993): Prosodic Morphology: Constraint Interaction and Satisfaction. Rutgers University Center for Cognitive Science Technical Report 3.
- Prince, Alan and Paul Smolensky (1993/2002/2004): Optimality Theory: Constraint Interaction in Generative Grammar. Blackwell Publishers (2004). [1](2002). Technical Report, Rutgers University Center for Cognitive Science and Computer Science Department, University of Colorado at Boulder (1993).
- Sanders, Robert Nathaniel. (2003). Opacity and sound change in the Polish lexicon. Ph.D. dissertation, University of California and Santa Cruz. ROA-603-0503, Rutgers Optimality Archive.