synchronic explanation

the aim of this article is to show that synchronic cognitive constraints are responsible for some restrictions on human speech sound patterns; not all markedness asymmetries can be ascribed to performance-based mechanisms of diachronic change. we identify evidence for synchronic constraints in sound patterns that are desirable from a performance perspective yet are not attested. we also discuss recent experiments that provide evidence for psychologically and even neurophysiologically active restrictions; these patterns can be distinguished from statistical generalizations across the lexicon. we also argue that there is evidence that language learning and adult well-formedness judgments are determined by innate predispositions. finally, we examine the methodology behind choosing a synchronic or diachronic account for a particular sound pattern when both potentially offer an explanation.