When my sons were little, I sang Mother Goose nursery rhymes to them.
All it took was a slight change, and they all fit into a melody I made up:

   Old mother Hubbard, she went to the cupboard
   To get her poor dog a bone
   When she got there, the cupboard was bare
   And the poor old dog had none, he did
   The poor old dog had none

I just added the "he did" or "She did" and repeated the last line..

   "And frightened Miss Muffet away, he did
    He frigthened Miss Muffet away."

My youngest son loved to sing along, even before he was talking, but he'd pipe in on the "he did" on every line.

Jerry