Use English outside your comfort zone.

Having taught at dozens of offices around Poland, we have come to see a strange phenomenon. Each office seems to have a special room where English is used, and once the people leave the room, they immediately go back to their mother tongue. Most, if not all, of your colleagues are in the same boat as you, so use the opportunity to speak with them in English. It may seem awkward at first, but you’ll get used to it and definitely gain confidence. You do it every day when you have to, right? Plus, it can be fun!