I just love that title. xD
If you're a linguist or studying that subject, the message of this book is nothing new: language is ingrown, dissheveled, intricate, oral and mixed (using the author's words here), who would have thought?
The thing is, many people still believe that language is something static that has to be documented to be real and anything away from the standard is worth less than this standard.
Admittedly, I am sometimes called a Grammar Nazi and people are right - it does give me the creeps if people use an apostrophe to mark possession in German (which is wrong, btw, though now it is okay if it's a proper name, much to my dismay) - or even the plural (*shudders*). I believe that in such cases people are just too lazy to care about the rules, and yes, I do believe standards are useful and necessary. I like to point out that one day someone wrote me a letter and mentioned "Kwalitet" ... it took me five minutes to understand what that person was trying to tell me. She meant "Qualität", btw. "Quality".
But apart from that? Yes, I try to use the genitive instead of the dative because I think it sounds nicer. (Speaking about German grammar again!) But more often than not I don't care, just as I heretically say that something makes sense, though in German the "correct" term would be "to produce sense" ... People can get really aggressive when it comes to that one. (If you ask German purists, English is a very evil villain indeed.) And just here, with using abbreviations like "btw", I contribute to the language decay that has infected the younger generations. I shall sit in a corner and weep with shame. Maybe.
Lucky me, there are people like John McWhorter who see language as what it is: something living, something changing and therefore irregular in some way or other. And with languages, all varieties are included; I won't elaborate much further, because this is actually not meant to be an essay, just let me say this: the author shows that even small varieties have their worth, and they are usually more complicated than languages with a certain prestige, such as English. Sure, English does have some grammar I constantly keep forgetting, and the pronunciation is really tricky from time to time, but there are no genders (for example) and even though there are some irregular verbs, there are regular ones, too. Out there, languages exist in which irregularity is the rule.
I haven't made up my mind about everything he said, yet, but generally speaking: this is a funny book for those who are interested in languages, and it should be compulsory reading for conservatives and purists. It's not hard to read, if any of you worried about that. The theory is presented without many technical terms and accompanied by many, many examples and case studies. (Though I should warn you: I now have the urge to learn some more languages. Especially Indonesian, just for fun.) If you already came to the conclusion the author draws, it might still be interesting to read about the different languages out there - at least some of them.