ABSTRACT
In high-performing urban schools, teachers help students master the vocabulary that serves as a gatekeeper to understanding challenging academic content. The gates of understanding swing open when students are fluent users of essential vocabulary related to the objective teachers want students to learn. Conversely, the gates of understanding tend to remain closed when students cannot converse using key words and concepts. The only students who reach a deep level of understanding are those who have integrated the key lesson vocabulary into their personal vocabularies. In every subject area (including mathematics, science, English, social studies, and others), students are likely to achieve mastery only when they have mastered the key lesson vocabulary.
