Optimality theory in morphology and syntax

The article gives a brief summary of work dealing with morpho-syntactic phenomena in OT, and also addresses more general problems. It highlights on questions of optimal ordering, optimal case, and optimal agreeement, including phenomena such as morphological gaps, repairs and case-split. It finally addresses the concepts of stochastic OT and bidirectional OT. key words: bidirectional OT, candidate set, case-split, constraint-ranking, faithfulness, harmonic alignment, lexical marking, optimal agreement, optimal case, optimal word, optimality theory, parallel optimization, repair, serial optimization, stochastic OT 1. Some basic issues Optimality Theory (OT) has originally been developed for dealing with phonological problems, abandoning the assumption that grammatical constraints are inviolable (Prince & Smolensky 1993/2004, McCarthy & Prince 1995). The fundamental new ideas have then soon been adopted in other grammatical domains, too, in syntax (Grimshaw 1997, Ackema & Neeleman 1998, Grimshaw & Samek-Lodovici 1998, Barbosa et al. 1998, Dekkers et al. 2000, Legendre et al. 2001) as well as in morphology (Legendre 2000, Wunderlich 2001). The main innovations of OT can be summarized as follows: (i) Grammatical constraints can conflict with each other and are violable under certain conditions (not inviolable, as assumed before). (ii) Grammatical constraints are ordered according to their respective weight (not equally ranked). (iii) Different rankings of constraints are responsible for differences between individual grammars or languages. (What was formerly conceived as grammatical parameters, is now reconstructed as constraints being differently ranked.) (iv) A construction is grammatical (not only by virtue of its own properties, or by virtue of its generative history, but rather) if it wins the competition in a candidate set, because it satisfies best the higher-ranked constraints. At first sight, many phenomena that had troubled linguists over years seemed to be good candidates for application of OT, such as variation in word order, selective blockings, morphological gaps, repairs, or the emergence of unmarked forms. However, as soon as one starts to analyze these phenomena more systematically, many important theoretical questions have to be answered: Must all the constraints belong to a universal set of constraints, or can there be languageor even construction-specific constraints, which are based on the instantiation of lexical categorization? Is it possible to represent cumulative constraints in situations where the effects of individual constraints seem to be added up? Which restrictions over constraints are necessary? Given the concept that each re-ranking of constraints defines a possible grammar, how can one avoid the problem of over-generation of grammars? And how complex does the OT architecture develop, if one assumes an infinite set of candidates, each with its own internal structure? Is it possible to restrict the set of possible candidates, that is, to define some relevant set of candidates? How is optionality to be dealt with (where more than one candidate seems to be optimal), and how ineffability (where no candidate seems to be optimal)? Can OT also cover the phenomenon of gradient grammaticality? And last but not least, how can an OT grammar be learned? (This last issue is dealt with in Tesar & Smolensky 2000.)