Whistling is the act of producing a sound by forcing air through a small opening, typically between pursed lips or through the teeth. This sound can vary in pitch and tone depending on the shape of the mouth and the force of the airflow. Whistling is often used as a form of communication, a way to express emotions, or simply as a musical expression. Many cultures around the world have developed unique whistling techniques, such as whistled languages that use specific patterns to convey messages. Whistling can also be found in various forms of music, where it serves as a melodic element, adding a playful or lighthearted touch to a song.