There are many stages to reading and yes, memorization is one of them. Here are some stages you may see your child go through.
- Point and label item in picture
- Look at the picture and create a story about that picture
- Look at the picture and create a story about that picture and connect the pages in the book (with the same story)
- Look at the picture and use actual words from the story (read like a teacher)
- Read the words in easy readers or memorize the stories
- Read the words and use the picture to solve unknown words
- Retelling stories
Here is a video to give you a few ideas of how to interact with your child when they know a book so well it almost sounds memorized. Once they finish you can have go back and solve a few words here and there for you or you can ask them to point under the words as they read.