Because I was author of one of the contests - I can say that problemsetters try to do everything possible to make statements clear. They work in cooperate with professional translator (delinur) to perform such a job. I think it's better than nothing :-)

There are many native english speakers on Codeforces. Maybe the Codeforces team can add one to the set testing team for each match to help make sure the English statements are clear. I find that the translators do a great job and feel most of the problems with clarity can be solved by this extra step.

I think lot of competitors read the statements in english, but they are not native english speakers. My english level is about intermediate, and sometimes I feel the statements level is higher than mine ( if I don't know lot of words than I try use dictionary). Sometimes I skip a problem because I don't understand the story clearly and we've got lot of problems so I try to solve some simpler statements problem. Sometimes if I have time I comeback that hard to understand problem. Maybe it's my fault because of the beginning of the competition I am little bit precipitant.

I think English translations in the recent contests have been very nice and much improved then before. It used to be a disaster some months back. But I think it has also to do with very unnecessarily long statements that problems used to have in the past. Thankfully now the problem statements have become shorter too. I mean seriously, we all enjoy a bit of a story around the problem, but let the problem be a contest problem, and not a piece for short story selections. ;)