The Word Generation program focuses on academic vocabulary, i.e., words that students are likely to encounter in textbooks and on tests, but not in spoken language. Interpret, prohibit, vary, function, and hypothesis are examples. Academic vocabulary includes (a) words that refer to thinking and communicating, like infer and deny, and (b) words that are common across subjects, but hold different meaning depending on the subject, like element and factor. Both types of academic vocabulary are likely to cause problems with comprehension unless students have been taught how to deal with them.