Alexander Bergs & Laurel Brinton 
Varieties of English [PDF ebook] 

This volume is one of the first detailed expositions of the history of different varieties of English. It explores language variation and varieties of English from an historical perspective, covering theoretical topics such as diffusion and supraregionalization as well as concrete descriptions of the internal and external historical developments of more than a dozen varieties of English including American English, African American Vernacular English, Received Pronunciation, Estuary English, and English in Canada, Africa, India, Wales, among many others.