Various 
Routledge Library Editions: The English Language [PDF ebook] 

This set reissues 29 books on the English language, originally published between 1932 and 2003. Together, the volumes cover key topics within the larger subject of the English Language, including grammar, dialect and the history of English. Written and edited by an international set of scholars, particular volumes employ comparisons with other languages such as French and German, whilst other volumes are devoted to specific English dialects such as Cockney and Canadian English, or English in general. This collection provides insight and perspective on various elements of the English language over a period of 70 years and demonstrates its enduring importance as a field of research.