We were guests in their country and if we wanted to communicate with them it was incumbent upon us to learn to speak in a way they understood. In the marketplace and in the villages, we spoke Chinese. In our home, though, we spoke English. This was our native tongue. This was the language we were most familiar with and most liked to speak.
Christians come from every nation and tribe.
Biblical language is Christian language. Many Christians want to do away with Christianese. Terms like born again and sanctified are offensive to unbelievers, they say. This is Biblical language, though. Whether we speak German or English or French we must speak of being born again and sanctified.