New Zealand English--at just 150 years old--is one of the newest varieties of English, and is unique in that its full history and development are documented in extensive audio-recordings. On the basis of these recordings, this book examines and analyses the extensive linguistic changes New Zealand English has undergone since it was first spoken in the 1850s. The authors, all experts in phonetics and sociolinguistics, use the data to test previous explanations for new dialect formation, and to challenge current claims about the nature of language change.