I love working in intercultural settings. So I'm very happy that I find myself in this situation again working in the Netherlands teaching an international class of students. All of us have English as a second or third language. Yesterday I swapped stories with colleagues. I shared that there are times when you simply don't understand what a student is saying. Depending on the situation, you decide whether you ask him/her to repeat it. At times, you think it's best to nod in agreement and really hope that it wasn't a question! Others shared how it works for them to fill in the empty spaces in what you hear with some empathy. And try to summary and check whether your understanding is right.
A pitfall in these situations is that you may confuse intellectual/analytical skills with skills to express oneself. Being aware of this pitfall hopefully helps. As a teacher, I try to work with as many signals about the students performance as possible (it's an experiential course without test exam). Therefore I attended some team meetings too. That really gave a different view as compared to the class situation. Furthermore, I stimulate students to communicate online by using e-mail or our google group. The google group has helped in two or three confusing situations to clarify the situation. In that way, the multiple channels seem to contribute to improve 'regular' communication in class and clarity about the work.