Origins of Canadian Raising in voiceless-coda effects: A case study in phonologization

Canadian Raising is the best-known of a diverse class of English allophonic height alternations in /ai/ conditioned by coda voicing. The alternations have been independently re-innovated and show a systematic typology: The voiceless environment selects the higher allophone. We hypothesize that the phonetic basis of the asymmetry is the tendency for diphthongs to assimilate to their nuclei before voiced codas and to their offglides before voiceless ones. Predictions are tested in an instrumental study of the development of a Canadian-Raising-like alternation in and around Cleveland, Ohio, in 28 speakers born between 1878 and 1977. Results support the hypothesis and contradict two widespread views about Canadian Raising, (1) that it arises out of the Great Vowel Shift and (2) that diphthongs are less diphthongal in the short pre-voiceless environment.