Badminton, like tennis, is a racket sport that is played by either two players or two teams of two players each. The object is for you or your team to get to 21 points first. You score a point whenever you successfully serve the shuttlecock and your opposing team commits a fault, which means that the team fails to appropriately return the shuttlecock.
Assuming one cares for their teeth by brushing regularly, saliva may smell bad because there are millions of bacteria present in the mouth. Bad smelling saliva or breath can be indicative of a tooth abscess, or a systemic illness such as diabetes.
Saliva is needed for the proper functioning of the tongue. A dry tongue can't taste a thing so saliva helps the tongue and our sense of taste by keeping it wet. Saliva moistens food and helps to break it down, which in turn makes it easier for the tongue to push the food to the back of the mouth for swallowing.