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

Elliott Moreton and Erik R. Thomas

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.

[To appear in: J. Cole and J. I. Hualde (eds.), Papers in Laboratory
Phonology 9.]