The document discusses vocabulary building and its importance. It explains that vocabulary expands with age and is fundamental to communication and learning. It notes that vocabulary matters as it improves communication and helps students think, learn, and comprehend reading. The document outlines three aspects teachers need to know about vocabulary: the form, meaning, and usage of words. It then provides examples of vocabulary from a passage about pollution, defining words like emission, contaminate, aerosol, interfere, radiation, environment, and quality.