Basically,improving one's english skills depends on how much time you spend practicing thes skills. the more you practice, the more skillful you are. However,graduate programs abroad do not allow students to practice their speaking skills because there is very little time to do so.Student have only a little time to discuss in group and then give a presentation just only for the final project. therefore. many international students have difficulty speaking english correctly,especially sutdents who hang out with other students with the same mother tongue. Hanging out with native speakers can help them improve not only their speaking skills but also their listening skills as well. Hanging out with native speaker can help them learn local idioms and about the culture too. For instance, I have heard many thai students complan in about having no friends and the fact that they are always worried about their studies and feel insecure about the american education system. I just advised them to go out with friends or find an activity the allows them to pratice language.Spending all of their time studying or locking themselves in the room day and night is not a good thing. I told them that you have more opportunities than other people,so why don't they explore their new enviroment instead of spending 2 or 4 years ina room as small as a prison cell.