Recent developments in contact linguistics suggest considerable overlap of branches such as historical linguistics, variationist sociolinguistics, pidgin/creole linguistics, language acquisition, etc. This book highlights the complexity of contact-induced language change throughout the history of English by bringing together cutting-edge research from these fields. Special focus is on recent debates surrounding substratal influence in earlier forms of English (particularly Celtic influence in Old English), on language shift processes (the formation of Irish and overseas varieties) but also on dialects in contact, the contact origins of Standard English, the notion of new epicentres in World English, the role of children and adults in language change as well as transfer and language learning. With contributions from leading experts, the book offers fresh and exciting perspectives for research and is at the same time an up-to-date overview of the state of the art in the respective fields.