This will be a review of John McWhorter's Our Magnificent Bastard Tongue published by Gotham Books in 2008. As far as I can tell, the author is linguist who is popular in the media. In addition to linguistics, he speaks about other contemporary social issues. For a lot of these academic popularizes, once you hear them often enough, you will see some of the same issues that they repeat with a difference. These are the key issues that they feel they should get across since they are important. Some of those ideas are found in this book.
Two of those ideas, I would like to bring up here. The first is that there are certain grammatical rules that must be followed is not necessarily true. This myth runs against two other ideas, which are that no language, including English, has a perfect consistent grammar and the other is that there is a fluidity to language such that it continues to change. The other idea, briefly, is that the Sapir-Whorf hypothesis is inconsistent when it is in its strong form. Both of these theses do not in a total fashion just concern English but other languages also.
Three main points about how the English language developed concern the Celtic, Norse, and Phoenician impact on proto-Germanic. These influences changed the way the language was spoken but the influence did not directly affect the way English was written at the time. This point illustrates the difference between written and spoken language. So these groups are responsible for the way English is used today, while the other ideas are about language in general. These five ideas correspond to the five chapters in the book.
One question to ask is, what of it? Perhaps the two points about the nature of language in general have their applications but the mutilation by non-native groups does not have an application for English speakers today. The point is not to restore English to how it was in the ancient past, but to acknowledge that mistakes in usage have led to the received way of how it is used. These are aspects that are not touched on much in most histories. This book, then, serves as alternate way of assessing how English came about.