In this paper we present the results of a trend analysis comparing acoustic vowel data collected from Australian English speakers over the past 40 years. Results reveal the final stage of short front vowel raising and provide evidence for subsequent lowering as a change in progress. We argue that this result reflects the reversal of a series of vowel changes that have been in progress for over 100 years. These findings raise interesting theoretical questions about the nature of vowel shifts and challenge Bybee's  assertion that sound change reversals cannot occur.
Bibliographic reference. Cox, Felicity / Palethorpe, Sallyanne (2008): "Reversal of short front vowel raising in Australian English", In INTERSPEECH-2008, 342-345.