[rant]
Bill, there are two other reasons for the decline of language in the U.S. which have been discussed in various places and the blame has been squarely placed on school boards and school administrators, the very people who ought to be encouraging better knowledge and use of language.

1. The adoption of standardized tests at various levels of schooling. These are supposed to show how well schools are doing and presumably if students are consistently doing poorly, corrective measures will be taken. What happens in practice is that no teachers and no schools want to look bad, so there has grown up the practice of "teaching to the test". The entire curriculum in the years in which students will take the test is geared almost 100% to the test. Everything else goes to the wall. Which means the students miss out on being exposed to a lot of literature and language instruction that they need. Also, in many places there is now a standardized test that every student must pass to graduate from high school. This also results in teaching to the test, since low graduation rates make the school and its teachers look bad.

2. "Dumbing down" and political correctness. Many school systems have reconstructed their curricula because too many students can't manage the old ones and they are failing. So the way to fix this is to make it easier to pass by requiring less. Then there are the school boards and administrators who have to make fixes which are motivated by PC. This means editing even classic works of literature (Huckleberry Finn is the favorite target for this in places where it hasn't been banned entirely) to avoid passages or words which might give offense to some students or their parents or pastors. Since there are plenty of people who will take offense at lots of expressions, this leads to a lot of bowdlerizing and censorship and, in extreme cases, to outright book banning. To me, all this is simply a form of book burning. I'd like to burn a lot of EdDs, PHDs, MATs, and other academic types who have no qualifications in the subject matter that the schools are supposed to teach and no idea of how to really get kids to learn. Also the pinheads on schoolboards who have no educational qualifications whatever but want to meddle in school policy and impose their own prejudices.
[/rant]