This is the first part of a two-part article on vocabulary instruction. This section will discuss the theories behind vocabulary acquisition. Part two will provide eight research-based methods for cultivating students' vocabulary.
The Central Importance of Vocabulary
Perhaps the greatest tools we can give students for succeeding, not only in their education but more generally in life, are a large, rich vocabulary and the skills for using those words. Our ability to function in today's complex social and economic worlds is greatly affected by our language skills and word knowledge.
In addition to the vital importance of vocabulary for success in life, a large vocabulary is more specifically predictive and reflective of high levels of reading achievement. The Report of the National Reading Panel (2000), for example, concluded, "The importance of vocabulary knowledge has long been recognized in the development of reading skills. As early as 1924, researchers noted that growth in reading power relies on continuous growth in word knowledge."
Vocabulary or Vocabularies?
In everyday conversation we speak of vocabulary in the singular; we speak of a person’s vocabulary. This is actually an oversimplification. The American Heritage Dictionary defines vocabulary as "the sum of words used by, understood by, or at the command of a particular person or group." In this article we are concerned with extending the sum of words that are used and understood by students.
However, it seems important to point out that in almost all cases there are some differences in the number of words that an individual understands and uses. Even the terms "uses" and "understands" need clarification. For example, the major way in which we "use" vocabulary is when we speak and write; the term expressive vocabulary is used to refer to both since these are the vocabularies we use to express ourselves. We "understand" vocabulary when we listen to speech and when we read; the term receptive vocabulary is used to refer to listening and reading vocabularies. Finally, to round out the terminology, meaning or oral vocabulary refers to the combination of listening and speaking vocabularies, and literate vocabulary refers to the combination of our reading and writing vocabularies. Are our listening, speaking, reading, and writing vocabularies all the same? Are they equally large? Is our meaning vocabulary larger or smaller than our literate vocabularies?
For the first five years or so of their lives, children are involved in the process of acquiring a meaning vocabulary—words that they understand when they hear them and that they can use in their speech. During this period, children have essentially no literate vocabularies. Most children acquire reading and writing skills upon entering school. They need to acquire a basic knowledge of how printed letters relate to the sounds of spoken words and how printed words relate to spoken words. Being able to translate or transcode print into speech allows children to use what they know about meaning vocabulary for their literate vocabulary. So for very young children, their meaning vocabularies are much larger than their literate vocabularies.
The acquisition of decoding skills leads to rapid expansion of literate vocabularies by allowing children to transcode their meaning vocabularies into their literate vocabularies. This is so much the case, that for older students and for adults, our literate vocabularies are probably larger than our meaning vocabularies. We tend to have a larger group of words that we use in reading and writing than we use in our own speech. This is because written language is more formal, more complex, and more sophisticated than spoken language.
High-frequency vocabulary refers to those words that are used over and over again in our communications. They are important to both our meaning and literate vocabularies. A mere one hundred words make up about 50 percent of most English texts; two hundred words make up 90 percent of the running words of materials through third grade; and five hundred words make up 90 percent of the running words in materials through ninth grade. If a reader is to have at least a modicum of fluency, it is critical that these words be taught systematically and effectively.
The research of Ehri (1994, 1998) is particularly informative. Her research strongly suggests that high-frequency words should be introduced without written context so that students focus on their visual composition, that they should be practiced in materials that are at an appropriate level of challenge, and that they should be practiced several times to allow developing readers to recognize them instantly or, in other words, at sight. She also makes the important point that although many of these words do not conform completely to phonic generalizations or expectations (e.g. was), they very frequently do have elements that are regular. For example, the w in was is regular and the s at the end of that word sometimes has the /z/ sound. Ehri's research strongly suggests that these phonic regularities are powerful mnemonics for remembering the words and should be pointed out, rather than expecting students to remember the vague shape of the word, as was the tradition with flash-card instruction for many years.
The Need to Improve Vocabulary Instruction
While the dependence of both general achievement and reading achievement on vocabulary growth has been clearly established for decades, those findings do not appear to have been put into practice. In a recent text, Beck et al. (2002) conclude, "All the available evidence indicates that there is little emphasis on the acquisition of vocabulary in school curricula." In a classic classroom observational study, Durkin (1979) found that in the 4,469 minutes of reading instruction that were observed, a mere nineteen minutes were devoted to vocabulary instruction and that virtually no vocabulary development instruction took place during content instruction such as social studies.
The effects of the lack of attention to vocabulary instruction, however, may not manifest themselves in the earliest grades where tests of reading achievement tend to contain passages that have simple content and common vocabulary. While most students who succeed in reading in the early grades continue to achieve well, some do not. The Report of the Rand Reading Study Group (2002) concluded, "Research has shown that many children who read at the third-grade level in grade three will not automatically become proficient comprehenders in later grades."
Indeed, a commonly reported phenomenon in reading test results is for achievement to be good through second or third grade, and to falter thereafter. This drop off in achievement seems very likely due to weaknesses in language development and background knowledge, which are increasingly required for reading comprehension beyond the early grades and for reading informational and content-area texts.
A study of international reading achievement provides some strong evidence that the weakness in U.S. student performance is not the result of decoding problems or inability to comprehend narrative texts. Instead, it seems to be due to weakness in ability to comprehend informational texts (Progress in International Reading Literacy Study 2003). When compared to students from the thirty-five participating nations, fourth-graders from the United States ranked fourth on the narrative section of the test, but thirteenth on the informational section. This disparity of nine rankings was by far the largest among the nations participating in the study.
It does seem hard to overstate the importance of vocabulary—not only for reading achievement but also for general social and economic success. The early years of a child's life have a profound influence on that child's language and vocabulary development, which in turn greatly influences school success. Children who live in poverty in their early years have much less verbal interaction with their parents and, consequently, begin school with far less vocabulary development than their more privileged peers. While the language gap doesn't widen once children from lower socioeconomic backgrounds enter the stimulating environment of school, that gap does not narrow. Research suggests that it may not narrow because the vocabulary instruction offered is not sufficiently intense or effective.
Beck, I. L., McKeown, M. G., and Kucan, L. 2002. Bringing words to life: Robust vocabulary instruction. New York: Guilford.
Durkin, D. 1979. What classroom instruction has to say about reading comprehension instruction. Reading Research Quarterly 14: 481–533.
Ehri, L. C. 1994. Development of the ability to read words: Update. In Theoretical models and processes of reading, 4th ed., ed. R. Ruddell, M. Ruddell, and H. Singer, 323–358. Hillsdale, NJ: Erlbaum.
Ehri, L. C. 1998. Grapheme-phoneme knowledge is essential for learning to read words in English. In Word recognition in beginning literacy, ed. J. L. Metsala and L. C. Ehri, 3–40. Mahwah, NJ: Erlbaum.
National Reading Panel. 2000. Report of the National Reading Panel: Teaching children to read. Washington, D.C.: National Institute of Child Health and Human Development.
Pikulski, J. J., and Chard, D. J. 2003. Fluency: Bridge from decoding to reading comprehension. Boston, MA: Houghton Mifflin Company.
Progress in International Reading Literacy Study. 2003. www.pirls.org.
Rand Reading Study Group. 2002. Reading for understanding: Towards an R&D program in reading comprehension. www.rand.org/multi/achievementforall.