While there is no American Academy to protect the English language, there are plenty of English style guides and manuals.France at least has the French Academy, which is charged soley with the protection of the French language. Any new words or slang are properly translated or added to the cultural dictionary they publish. If it's slang they even instruct you on the proper way to spell and write it. That would never work in the States but at this rate handwriting and correct English will be gone very soon. Replaced with Yo YO- what it be? Utah wants to eliminate the 12th grade to save money. How about more instruction- we just keep dumbing it down.
Very sad.
One is the web based The English Style Book.
Amazon has several options including Plain Style: A Guide to Written English, The New York Times Manual of Style and Usage and The Elements of Style: 50th Anniversary Edition.