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. The rich corpus of spoken language provided by New Zealand's 'mobile disk unit' has provided insight into how the earliest New Zealand-born settlers spoke, and consequently, how this new variety of English developed. 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. The first ever corpus-based study of the evolution of New Zealand English, this book will be welcomed by all those interested in phonetics, sociolinguistics, historical linguistics and dialectology.