When we learn to reading by playing with sounds first, the skills develop naturally. Using mirrors and sound play we allow students to discover for themselves how their speech sounds relate to written words.
When you are led to discover things for yourself, you created a stronger memory than if someone simply tells you "make the letter P sound with your lips and a swift gust of air from your mouth." Most children enjoy watching themselves in a mirror. Why not use that engaging activity to increase their knowledge of how the sounds they make become words on a page!
Playing with the sounds in both real and "alien" or nonsense words create strong neural associations that helps increase the speed and accuracy of reading and spelling.