Phonetic reduction can lead to lengthening, and enhancement can lead to shortening

Contextually probable, high-frequency, or easily accessible words tend to be phonetically reduced, a pattern usually attributed to faster lexical access. In principle, word forms that are frequent in their inflectional paradigms should also enjoy faster lexical access, leading again to phonetic reduction. Yet research has found evidence of both reduction and enhancement on paradigmatically probable inflectional affixes. The current corpus study uses pronunciation data from conversationally produced English verbs and nouns to test the predictions of two accounts. In an exemplar account, paradigmatically probable forms seem enhanced because their denser exemplar clouds resist influence from related word forms on the average production target. A second pressure reduces such forms because they are, after all, more easily accessed. Under this account, paradigmatically probable forms should have longer affixes but shorter stems. An alternative account proposes that paradigmatically probable forms are produced in such a way as to enhance not articulation, but contrasts between related word forms. This account predicts lengthening of suffixed forms, and shortening of unsuffixed forms. The results of the corpus study support the second account, suggesting that characterizing pronunciation variation in terms of phonetic reduction and enhancement oversimplifies the relationship between lexical storage, retrieval, and articulation