Coordinated and local optionality in Serial Noisy Harmonic Grammar

Various implementations of Serial Noisy Harmonic Grammar (SNHG) are tested against two optional processes that exemplify different kinds of optionality. Eastern Andalusian’s vowel harmony shows coordinated optionality, in which all posttonic vowels, e.g., must harmonize (or not) together. French schwa deletion/epenthesis lacks coordination: realization of one schwa does not require realization of another. SNHG is shown to produce coordination only when it perturbs constraint weights (rather than harmony scores, e.g.). Furthermore, under a theory of gradualness in which each vowel requires multiple steps to harmonize, weights must be perturbed once and for all at the outset of a derivation, not separately on each step. This version of SNHG also accurately models local optionality in French, suggesting that it provides a general account of various kinds of optionality. The crucial factor setting it apart from other versions of SNHG is that it does not permit harmonically bounded outputs. This result is consistent with existing assessments of parallel NHG, suggesting that perturbation of weights is a robust formalism for optionality no matter the larger theoretical context.