It's good to start reading to your babies as soon as possible and show them words and pictures that are big and by itself as in flashcards when they are small. This is based on my experience using Glenn Doman's methods. If you can get your hands on

his book on "How to teach your baby to read", you will understand the more proper methods to use.  The idea is also to do it  regularly and repetitively when you show them pictures and words. When they are able to read a bit, I started my children on the ladybird series, of Peter and Jane. They had very few words at the start and the words are repeated a number of times in each book throughout  the series. My children are in their teens now and they love reading and they read very fast. I believe it is through the flashcards and reading to them at an early age that they now have very good memory as well.