Why does language change? Why can we speak to and understand our parents but have trouble reading Shakespeare? Why is Chaucer's English of the fourteenth century so different from Modern English of the late twentieth century that the two are essentially different languages? Why are Americans and English 'one people divided by a common language'? And how can the language of Chaucer and Modern English - or Modern British and American English - still be called the same language? The present book provides answers to questions like these in a straightforward way, aimed at the non-specialist, with ample illustrations from both, familiar and more exotic languages.
I don't have the expertise to rate the quality of information contained in this book, I consider it a valuable read, for me at least. I began reading the book as I was beginning the section on language change in a survey linguistics class I was taking, so at first what I was reading in the book was a healthy and enriching extension of what I was learning in class. This would be a good book to own, for someone interested in the topic, as it covers many areas of historical linguistics, comparative linguistics, and language change. One of the authors, who teaches at Ohio State University, writes on his university profile that the book is intended for undergraduate students of linguistics, and that seems about right. It's thick with information but not so thick as to be over my head at this point.
Perhaps the most complete book that I have come across related to historical linguistics. Some sections become repetitive sometimes, but it's normal since many phenomena are very closely related (e.g. language contact, borrowing and lexical and semantic change). Totally recommended.