Whistling is the act of producing a high-pitched sound by forcing air through a small hole in the lips. It is a common form of nonverbal communication, often used to get someone’s attention or to express a feeling such as happiness or surprise. Whistling can also be used as a form of musical expression, with some people able to produce complex melodies and rhythms.
There are many different ways to whistle, but the most common method is to purse the lips together and blow air through the small hole created by the opening. The pitch of the whistle can be varied by changing the shape of the lips and the amount of air blown through the hole. Some people can also whistle by using their teeth or a blade of grass.