It is really hard to say. If the 'communication' you mentioned is merely a short dialog of greetings and simple asking and answering a few questions, then it is not an achievement can be classified by a grade. However, if you really can carry out freely an English conversation with people who can speak fluent English, then your English, at least oral English, has reached a level of a university graduate, which you can take it as grade 4. Maybe it can be marked as IELTS 5.5-6.0.
