Or else, bacteria, insects and unwanted calories will be engulfed leading to diseases, obesity and other undesired troubles.The tongue behind will kill you if you inadvertently and imprudently overuse it.
See, the creator of human body ''God'' has kept nose and ears permanently open and eyes also open most of the time, except while sleeping. However, mouth has to be kept closed all the time except for speaking and eating.
So think before opening mouth again! See that you keep on trying to keep your mouth shut, as much as possible.