The actuation problem in Optimality Theory: Phonologization, rule inversion, and rule loss

This chapter outlines OT’s contribution to research into the actuation of phonological change. We examine both phonetically driven innovation and analogical change (particularly rule inversion and rule loss).
Following Ohala, we assume that the phonologization of mechanical phonetic effects is caused by parser malfunction. It is therefore suggested that, as a theory of grammar, OT will play a secondary rôle in accounts of phonologization. Nonetheless, OT makes a significant contribution in this area by modelling the restrictions that universal markedness principles impose upon phonological innovation. In this connection, we argue that markedness generalizations are not mere epiphenomena of performance-driven change, and we refute the claim that inverted phonological processes are synchronically arbitrary.
In the area of analogy, the optimality-theoretic concept of input optimization affords new insights. We observe that most types of analogical change involve the restructuring of input representations at some level in the phonology. Restructuring usually occurs when, as a result of some independent development, learners cease to encounter positive cues to abandon their default state, in which input representations are identical with the corresponding outputs. We show that, whereas OT predicts this state of affairs, rule-based theories cannot account for the facts without imposing contradictory demands on acquisition theory.
Our discussion of analogy is illustrated with a case-study of rule inversion and rule loss in the late West Saxon dialect of Old English. The analysis is couched in the framework of interleaved OT. It is shown that, unlike strictly parallel approaches to the phonology-morphology interface, interleaved OT preserves and develops the best insights of Lexical Phonology into the life cycle of phonological processes.