Difficult Questions for Me

Sometimes, we can see people from foreign countries in our hometown. And some of them have to ask us some questions. As you know, not all of the Japanese can speak English correctly, and some of them cannot speak it at all. How do you communicate with the foreigners when you cannot speak English? We often have conversation troubles like that.
I learned it is the most important thing to have communication with foreign people is not try to speak English correctly or perfectly. The most important thing is to say something that you want to say in English. It doesn’t matter it is correct or not.
I think this is one of the answers for many conversation troubles, but it cannot be true all the time. If it IS the answer, why have you studied English so long time? Did it go wrong? I don’t think so. The way we have studied English is right and it is the correct English, I think.I want to be an English teacher in the future, and I didn’t want to learn such a way to speak English. I know it is the practical way, but if I said it is the right way to communicate, how can I teach to my students English? Do I have to say “You don’t need to study English correctly. Take it easy. You don’t need to study English because you won’t speak much in the future.”? What is the correct answer? I’m confused recently. And I think no one knows the correct answer for every thing.