Well I've just about finished reading "The Mother Tongue: English & How It Got To Be That Way", by Bill Bryson. I'm close enough to finished that I can make some comments on it, if I want. I have a fine history of reviewing books I havent read, movies I havent seen and bands or musicians I havent listened to, so that fact that I have a few pages to go before finishing it should not worry anyone.
This is a "popular" history of English, meaning that the author explains any big words he uses. Its not a text book, and tho you may be able to find useful tid-bits to flesh out a college course, you probably would not be required to read it or buy it or even know about it. The book does assume you have basic (perhaps slightly more than basic) knowlege of English grammar. But even if you dont, you'll be ok.
I have a degree in history (minor in political science, so why am I so apolitical? Thats another post) and I enjoy reading histories of things. Now I have to warn anyone studying history in college, even at the graduate level, be careful of "History of" courses offered by other departments. History of the Language, offered by your local English Department, is not a history course. It is a language course, and the fact that the language is English does not make it any easier. It is HARD. You need something other than a social studies background before you tackle that one. I was cruising along getting A's & B's and suddenly I found myself struggling to get a C, and was happy that I got it. I'm a slow learner, because then I tackled History of Philosphy - a course you could take as a senior or grad student for crying out loud. I remember with fondness the 4 or 5 minutes of actual history taught in that course. I felt so comfortable & right at home. But then it dissolved right back into electrons and dark matter (before people knew what to call it), and I thought, Albert Einstein would be comfortable in this class. It was nature of the universe stuff, not ideas espoused thru the centuries. I dropped it. I was lost, I would have failed it. So be careful about "history of" courses. Except Political Theory - I ate that stuff up.
Mother Tongue is more a history of words in English and how they got that way, (to paraphrase the title) as opposed to the course I struggled with back in college. I remember chapters on Spelling, the differences between American & British English, Meanings, Dictionaries, where words come from, swearing (I swear), pronunciations and so on. Its a very good book if you like words and usages. Tons of examples, anecdotes, humor, and a much greater amount of History than there ever was in that History of the Language course that about ate me up. If nothing else, you'll find out how it came to be you arent supposed to split an infinitive in English, or end a sentence with a participle.
So if you had proper scientific instruments, instruments sensitive enough, after reading this book you'd almost certainly notice a slight increase in the amount of knowlege you store in your brain. And that has to be worth something.