Comfortable in your own language

I work in a foreign based financial institution and so I hear a lot of different languages. Although everybody speaks English when two different language speakers want to engage in a conversation but when two people of the same language team up, they try to speak the language of the native tongue. It is not that I am talking about just other people but it is I also that when I meet somebody of the same language that I speak I converse in that language. Although I am fluently conversant in both languages, but I feel that when I speak with the other person of the same language, they don’t want to have conversation in English language when they already know they can express themselves and be more comfortable in their native tongue. And no matter how conversant or fluent you are in another language, you always tend to gravitate to your own mother tongue. There was a study long time ago that when the language you are hearing or speaking or wants to speak is not your mother tongue if you hear it then you translate it first into your mother tongue and then say it in the non native tongue. And if you are like me you may have seen numerous instances where you get emails in English which are it seems translated literary from the Native tongue and it sounds sometimes funny and sometimes makes no sense. So next time you should notice this for yourself that if you meet someone from your own mother tongue you will naturally gravitate to speak in that language even if you know perfect well other languages since that is the most comfortable you feel in.