How could you convince a small child that when you speak, it is not necessary for air to travel from your mouth to the ear of a listener?
Take a slinky end tie one end to the wall and give the other end a push or pull alternately Compressions and rarefactions move towards the wall i.e. wave moves but the parts of the slinky just vibrates about Its mean position.
In the same way compressions and rarefactions are produced in air and no net movement of air particles is required for sound to travel.