My son doesn't make his own lyrics up that often, but there were times when he wanted to know the exact lyrics to a song he had heard (Magic School Bus theme song comes to mind), and because he was a very early reader, we would look the lyrics up on the internet and print them out for him. As a result, I have videos of a three year old walking around the house, singing at the top of his lungs from a song sheet like a little choir boy. They're hilarious.