Katerinka: American students tend to read novels and write compositions in their English classes. Grammar is usually not taught, although I had one teacher in the eigth grade who was an exception(it is there where I learned what direct and indirect objects are). As for spelling, there is not so much emphasis on spelling rules as on learning random vocabulary words and being tested on spelling them correctly. A fair amount of kids seemed to have problems spelling in the earlier years, but I don't remember anyone in high school who couldn't spell more or less correctly.
I do believe that English is not that difficult to become functionally fluent in. Of course, it may take many more years before people get the articles and tenses completely correct.