Being serious, where I work is full of European engineers. We all converse in English, in the main, but they often speak to each other in their respective languages. These are highly educated people but you have to accept that it's more natural for them to converse in their native tongues. Most of us know a few pleasantries in French, Italian, Spanish, etc. and use them where appropriate. It goes a long way towards making the place friendlier and a nice place to be.