It isn't the country of origin, but the posters motivation and attitude that is the problem.

I recently recruited a girl from another forum, and she has joined my fit to talk project. She is from Venezuela, and her first language is Spanish. Her English skills are 'mid-range'. She has just managed to obtain an information technology degree in a country that is in economic and political chaos. Banning people like her would be a loss to the forum in my opinion.

I suffer from the same frustrations as the OP, and I have suggested a variety of solutions. One obvious one is the restriction of new posters to certain boards until the community has awarded them a few merits for their posting skills. Another is heavier moderation to delete useless spam posts, and the locking of spam fest threads. I believe it would be useful to lock threads that have not been active for a couple of months as well.