Think of your brain as a library. Every experience you’ve had, everything you’ve learned, read, seen, heard, tasted, felt, every good and bad memory, all stored on shelves for your reference. When you encounter something new, you can go back to your library for help understanding it and use things you know from the past to help you make sense of this new information.
For an adult with typical hearing and cognitive skills who is a native speaker of the language (let’s say English, in this case, but it can be any language), that library is quite large! You have lots of life experiences that you can use as clues to help you figure out new things you don’t yet understand or as references to fill in the blanks when you miss some information. For example, if you’re talking to someone and you hear them say, “Don’t cry over spilled…” but you miss the end of the sentence, you can draw from your library to know that the message was, “Don’t cry over spilled milk.” You’ve probably heard it dozens of times before. And more than just knowing what was said, thanks to your library, you also know the meaning of that saying: Don’t worry about something that has already happened. You can’t go back and fix it. It’s minor. Move on. A good mental library is a powerful thing. It helps you fill in the blanks, make up for what you missed, and integrate and understand new information.
But children, even hearing children, are working with a much smaller reference library than you, the adult with a complete language system. They are still learning the language, and they have fewer experiences to draw from to make sense of the world. Children with hearing loss are at an even greater disadvantage, because they have missed some early months of hearing before they received hearing technology and their capacity to overhear (“incidental learning”) is reduced. We’ve got to make up for this and help them build their libraries with redundancy.
Let’s take the example of learning a new word. If I say to you, “I had to take my car to the shop because it needed a new serpentine alternator,” how would you understand this new term?
Internal redundancy is your brain reference library. You hear something, and you have many references inside your hear to help you make sense of it. Maybe you’ve heard the word before, or you can use context clues in the sentence to figure it out, or you have an experience in the past that will help you understand it, or you can predict using patterns you know from the past. Adults (with intact hearing and a complete language system and typical cognition) have great internal redundancy. You may not know what a serpentine alternator is off the top of your head, but you can use context clues, like “car was broken” and “took it to the shop” to guess that I needed a new car part. You might guess that serpentine is the same as serpent and this has something to do with the snake-like manner in which that part moves. You might know what an alternator is, or at least what “alternate” means, and be able to guess the function of the part. Using your reference library, you can put together the pieces of the puzzle to figure out the meaning of the sentence. For children, this task is much, much harder. They lack the high degree of internal redundancy that most adults have.
So instead, we must increase the external redundancy. If you don’t have a match for this in your brain library, I’m going to have to increase the models you experience outside your head to help you build it. I might repeat the word, or use it in various contexts, talk about its meaning, show you a picture, write it down, or do other things to help you build that library in your brain, so the next time (or the next time or the next time or the next time) you encounter this word or phrase, you have a little more internal redundancy to work with to help you figure it out. There’s no need to be a broken record. In fact, experiencing the new word (or phrase, or concept) in many different contexts actually helps it to stick.
It’s an inverse relationship. When internal redundancy is high, external redundancy can be low. An adult can hear something once, or hear a partial message, and still get it. When internal redundancy is low, external redundancy needs to be higher to achieve the same result (comprehension).