Lolita Vampiriá said:
Don't they teach English in schools in the USA?
a cautious answer to that could be: languages where the pronunciation of words differs a lot from the actual spelling are, generally speaking, harder to master in writing than languages where the two are closer. amongst the indo-european languages i know (of), english and french seem to present a wider divide. a native italian, spanish, or german speaker is likelier to be able to infer what the correct spelling of a word is, when he's
heard the word much more often than he's
seen it. exceptions and pitfalls, along with a mixed origin of most words, make this a harder task for english and french speakers. if you pay attention to some of the most common spelling mistakes in english, for instance, you'll notice that they're made trying to replicate the way the word
sounds, so that - phonetically - it still works.
another cautious answer is that we mostly see english native speakers writing in their own language on communities online, and therefore don't really have a well-documented idea of how many spelling mistakes people who are native in another language would make. it could be that an italian, spanish, german, or finnish community would have users as prone to typos and grammar blunders as the english speakers we see on international sites.
a less cautious answer, however, could be that the level of literacy among your ordinary joes in the united states is lower than it is in europe - provided we compare categories that share at least class and age. and since, on the contrary, the spreading and use of internet resources is far more advanced there than here, reaching younger and poorer people, the percentage of ignorance that transpires on public sites is higher.