Babies love to hear nursery rhymes.  For each of the 20 lessons I have suggested a nursery rhyme for you to recite and/or sing for your baby.  Try to memorize the rhyme yourself so you can repeat it for your baby often, over the 2 week lesson period.  I personally like to alternate between speaking and singing the rhyme to provide a greater learning experience.  Suggested times to share each nursery rhyme are while changing, dressing, feeding, cuddling, rocking, etc.