I could draw out this concept on a whiteboard, chalkboard, or sketchpad style animation. I think this could be a fantastic way to elucidate the concept. At each word, I could erase a, and the thing could go through an interesting transformation. The reaction by the people would be funny and make the point that the "A" is very important to our world. The narration would be a gentle, childlike voice or a cool, young adult style voice. The music would be friendly and laid back.