Heaps' law

Heaps' Law is a way of predicting how many words you need to learn in a language or to understand a text. It says that the number of words you need to know increases as you learn more and more. In other words, it takes more and more words to understand something as you learn more. For example, if you want to understand a book, you'll need to learn more and more words as you keep reading it to truly understand it.