It’s been a little too long since I read this to write a detailed review, but on the whole I found it readable and interesting. At times it began to feel belaboured in terms of the examples given and the detail gone into, though of course, I’ve also read various other books about linguistics and so I had some grounding in what I was reading already. For the most part, McWhorter avoids being prescriptive about language and tracks change in language as how language works — which you’d expect, or hope for at least, in a linguist, but it isn’t always the case.
There’s some interesting stuff particularly on creoles and pidgins, which somewhat debunks the idea that a pidgin becomes a creole through children speaking it, etc. Not that there’s no truth to it, but McWhorter complicates the picture a little.