A common misconception is in order to be literate a person must be able to comprehend words. Reading words is a big part of literacy and very important, however it is not the most essential aspect. I feel literacy is mainly about being able to attain and retain a message from a source (books, letters, text). There are other visual representations that can do this just as well.
With Valentine’s Day coming up the message that a lot of people want to give to one another is “I love you” or “I care about you”. Writing these words on a Valentines card or something else will definitely give the message to the other person. However this message could possibly have the same or more meaning if say a child gives their guardians a drawing of their family on a paper heart. Or maybe an individual who is in another country can send the person they care about a picture of them self. These messages can say something meaningful without using a single letter.
The key is to use visuals that are meaningful to the reader in someway. For example the book Arrival by Shaun Tan is a wordless picture book could have easily had words to explicitly display meanings. Instead this story allows the reader to interpret the message that they find however they want to. There are some who see a man using his own special kind of literacy to communicate with his family. The message I take from this story is while loved ones may have to leave, they will always be with you and you will be able to see them again.
This form of literacy is important and is also what a lot of children use before they can learn to read. What adults can do is continue to show children the importance of attaining meanings from visuals. Even as an adult a picture can say a thousand words.