Bjarke Frellesvig describes the development of the Japanese language from its recorded beginnings until the present day as reflected by the written sources and historical record. Beginning with a description of the oldest attested stage of the language, Old Japanese (approximately the eighth century AD), and then tracing the changes which occurred through the Early Middle Japanese (800–1200), Late Middle Japanese (1200–1600) and the Modern Japanese (1600–onwards) periods, a complete internal history of the language is examined and discussed. This account provides a comprehensive study of how the Japanese language has developed and adapted, providing a much needed resource for scholars. A History of the Japanese Language is invaluable to all those interested in the Japanese language and also students of language change generally.

- Separates each period into different parts, providing a clear chronological basis for analysis - Traces the changes that have occurred in the language from Old Japanese to Modern Japanese - Analyses phonological changes as well as those within grammar and vocabulary