We have a pretty low tolerance for reading unknown words. And writers use a lot of words, many more than speakers do. If I’m talking about my cheap friend, I might use the word cheap three times within a few sentences. But writers like to mix things up, so my friend will be “frugal,” “stingy,” “thrifty,” and “tight.” Texts that students typically encounter in school have about 85,000 different words. Somehow we need to ensure that children have a broad enough vocabulary so that they are not constantly colliding with unknown words.
Excerpted from: Willingham, Daniel T. The Reading Mind: A Cognitive Approach to Understanding How the Mind Reads. San Francisco: Jossey-Bass, 2017.