Optimization-based modeling of speech timing

An optimization-based model of suprasegmental speech timing is presented.Timing patterns are modeled by trading off economy and clarity-related demands.Global and local weights allow for simulating different prosodic conditions.Simulation experiments demonstrate replication of various timing phenomena. We present a model of suprasegmental speech timing based on the assumption that speech patterns are shaped by global and local adjustments of trade-offs between conflicting demands of minimizing production effort and maximizing perceptual clarity. The model uses an optimization procedure to determine durations of suprasegmental constituents of simulated utterances by minimizing an independently motivated composite cost function. The cost is a function of the constituent durations and encompasses different components that represent independently derived measures of speaker-based production effort, listener-oriented perceptual clarity as well as time conceptualized as a resource shared between both parties, linked to transmission efficiency. The trade-offs between these influences can be globally and locally adjusted by weights assigned to individual cost components within the composite cost function. We show that this approach facilitates modeling a hierarchy of interacting prosodic features of utterances, such as different degrees of prominence or effects of speaking rate and overall requirements of clarity. We outline the theoretical foundations and the architecture of the model and present results of simulation experiments, demonstrating that the model correctly predicts a range of suprasegmental timing phenomena in stress-accent languages that have not been addressed by a unified model. Results underline the model's capacity to account for several empirical observations regarding durational variation in speech.