When emergency workers arrive at an old firehouse in New York City, the way they greet each other is not what you might expect. These first responders say, "Ni Hao!” “Ni Hao” means hello in Mandarin Chinese. First responders are the first emergency workers to arrive at a fire, traffic accident or other emergency. Some first responders are fire fighters, while others can be Emergency Medical Technicians -- also known as EMTs -- or paramedics. In Brooklyn, New York, over 20 first responders are studying Mandarin Chinese for about two hours a week. The class is the first of its kind. It is offered by the Fire Department of New York's Phoenix Society and the New York City Fire Department Foundation. New York City is a diverse area. The U.S. Census Bureau recently reported that some New York neighborhoods are made up mostly of immigrants. Some people have predicted that the Chinese community is likely to become New York's largest immigrant group. They think the city will have the largest Chinese community outside of Asia.