Vocabulary instruction is an important part of schooling because word knowledge is a critical factor underlying reading proficiency and overall success in school. Several considerations are important to understanding what constitutes effective vocabulary instruction. First, the number of different words in material read by US students is huge, probably in excess of 100,000 words. Most students learn a sizeable number of these words by the time they complete high school, probably 40,000 to 50,000 of them. Other students—including some English learners and some children of poverty—enter school with vocabularies much smaller than those of their linguistically and economically advantaged peers and are at a considerable disadvantage in learning to read and in succeeding in school.

An instructional program powerful enough to assist both those students with strong vocabularies and those with weaker ones learn the words they need to succeed must be comprehensive and multifaceted. One such program consists of four components: The first component is providing rich and varied language experiences. This means giving students many experiences with listening, speaking, reading, and writing at all grade levels. The second component is teaching individual words. This is what most people think of when they thing of vocabulary instruction. Some matters to consider when planning to teach individual words are how to create powerful instruction, when to use powerful instruction and when to use less powerful but much less time-consuming instruction, and how to select words to teach. The third component is teaching word learning strategies, strategies such as using word parts, context, and the dictionary to learn words. With tens of thousands of words to learn, students need to develop ways of learning words on their own. Something to keep firmly in mind when teaching strategies is that teaching students to effectively use strategies is going to require considerable time and effort. The final component is fostering word consciousness. The term word consciousness refers to an awareness of and interest in words and their meanings. Students who are word conscious are aware of the words around them—those they read and hear and those they write and speak—and they work to find ways to use words more effectively and understand their subtleties.

We know a great deal about vocabulary learning and vocabulary instruction. A comprehensive approach to vocabulary instruction like that just described can help all children learn the words they need to succeed in school and in the world beyond school. At the same time, there is a lot to learn if vocabulary instruction is to be as effective as possible: There is the need to develop a current and comprehensive inventory of the words kindergarten through 12th grade students are likely to encounter in the materials they read both in school and out of school. There is a need to identify the words likely to be known by students of different ages and various linguistic and socioeconomic backgrounds. There is a need for improved approaches to selecting vocabulary to teach. There is a need to create vocabulary building programs that are lengthy enough and substantial enough to markedly increase the vocabularies of students whose vocabularies are much smaller than those of their classmates. Finally, there is a need to create differentiated instruction to meet the needs of students in the same class who possess very different vocabularies.