The difference between these two mistakes may seem unimportant to a lay person, but to a cognitive psychologist it is crucial for understanding how language development occurs. In order for us to construct meaningful language, we must learn how to suppress things we’ve already said. In addition, we must learn how to activate in memory what we are currently trying to say and what we are about to say. Children haven’t learned how to suppress in memory what they’ve just said or how to activate in memory what they’re currently saying. A brain-damaged patient may make similar errors if the part of his or her brain responsible for this kind of memory suppression and activation has been harmed. And an adult repeating a tongue twister might make this kind of error because the brain is processing so much unusual information that it temporarily loses its ability to perform these activating and suppressing activities.