It is not going to work if I ask everyone to speak English and I dont want to become a laughing stock.

Sign language is good as long as you are telling the directions but in an engineering office you cannot rely only on signs.

Before leaving that office I am going to arrange an English Teaching Course conducted by Mullah KnoxCollege. And at the end of the course I will ask them that hopefully now they have learned English so kindly communicate in English. But I still have six months to go in this multi-cultured office.