Lexical Exceptions in Stress Systems: Arguments from Early Language Acquisition and Adult Speech Perception

Some, but not all, languages with fixed stress exhibit lexical exceptions to their stress rule. Under the assumption that lexical exceptions can occur in a language only if its native speakers can perceive stress contrasts, I argue that the presence of these exceptions depends on the age at which infants discover the stress rule of their language. If the stress regularity is easy to infer from the surface speech stream, then it will be acquired very early, and stress will not be encoded in the phonological representation of words in the mental lexicon; as a consequence, stress contrasts are not well perceived by adult speakers and lexical exceptions are excluded. If, by contrast, the regularity is difficult to infer, then it will be acquired relatively late, after the format of the phonological encoding of words has been fixed. That is, stress will be redundantly encoded in the mental lexicon, and lexical exceptions can thus be perceived and stored by adult speakers. A typological survey concerning the occurrence of exceptions in languages with fixed stress supports this proposal. A comparison with a metrical approach to exceptional stress is made, leading to a proposal about the division of labor between psycholinguistics and theoretical phonology.