How do vibrations cause sound waves

Sound consists of compression waves in some material-usually air. Sound waves are created by the vibration of some object or even air itself. They can be created by a back-and-forth motion of an object, by having air pass over a vibrating object, or by moving air causing the vibrations.

sound waves are a type of wave sometimes called compression waves, vibrations with enough of an amplitude can compress and decompress the air adjacent to the object causing the waves to form.