The question is "Do you think that the international student's difficulties with grammar and vocabulary are likely to cause them the most problems when writing in English?" According with my experience, the most difficult part of writing in English is the style. The most of the time I translate literally but I do not realize that writing in English supposes to organize the phrases and paragraphs in a different way if we compare with Spanish language. For doing this well is necessary to gain a lot of experience. I think that vocabulary and grammar could improve quicker than the style for writing in English.