The first time a reader encounters an unknown word, the reader has several options. One option is to skip the word. When encountering the occasional unknown word, a reader will often skip it if it does not affect the overall gist of the passage. The reader, however, does store away one or more aspects of the word (that is, they remember something about the word; perhaps a spelling pattern or the context in which the word occurred). The reader may also search for familiar word patterns, such as known prefixes or word roots. After each encounter with the word, the reader stores away more information until eventually the word is known. Multiple exposures to a word are essential if the word is to become part of an individual’s vocabulary. Nagy and Scott (2000) cite research showing that after 40 encounters with a word, students were still extending their knowledge of the word.
Adult learners may have an oral vocabulary that is larger than their reading or writing vocabulary. This means they have heard and can use in speaking many more words than they can decode. As their decoding skills improve, the difference between their oral and reading vocabularies may decrease. In addition to this, explicit teaching of new vocabulary is needed to ensure, they are able to understand the longer, less familiar words they will meet in more sophisticated or specialised texts.
Studies of vocabulary have shown that a basic 2,000 word vocabulary of high-frequency items enables a reader to understand approximately 80 percent of the words in an academic text37 (select here for a discussion of academic vocabulary and texts). At this level, however, the learner will probably not be able to extend their word knowledge independently – 95 percent coverage is needed before learners can successfully guess the meanings of unknown words.38 Different levels of knowledge about a word (that is, variations in how well a word is known) can become apparent in contexts where detailed knowledge may be needed because of the degree of precision and expertise required. A reader without specialised knowledge may know a word well in everyday contexts, but in specialised contexts the same word may take on particular meanings. For example, most people know and use the word hormones, but when listening to a talk or reading an article by a doctor, they may find that they don’t have a deep enough understanding of the word to fully comprehend the talk or article.
The vocabulary that adults need to use in academic work, particularly in reading and writing, is different from the vocabulary they need to use for everyday interactions. The 2,000 word vocabulary that allows for 80 percent of the words in most texts needs to be expanded to include useful words that appear across a wide range of academic texts.
A well-recognised list of such words is the Academic Word List (AWL) developed by Averil Coxhead.39 This list comprises 570 word families and can account for as much as 10 percent of the remaining words in a text (that is, those words not in the 2,000 high-frequency word list).
The words in the AWL are likely to be more than one syllable long and to be abstract rather than concrete. These words express abstract notions (for example, ideology, capacity and phenomenon), descriptions (for example, ethnic and compatible), processes (for example, decline and trend) and aspects of academic tasks (for example, define, demonstrate and contrast). Half of the high-frequency words and two-thirds of all academic and technical words are derived from Latin, French and Greek. This indicates the importance of learning the meanings of Latin, French and Greek roots and affixes.
The remaining vocabulary challenge for learners is to read the relatively small numbers of technical (subject-specific) words as well as small numbers of low-frequency words. While these words may appear a number of times within a specific text, the general reader is not likely to meet them again for a long time. However, it is the 2,000 high-frequency words and the academic words that will provide almost all of the vocabulary needed for reading.40
Other useful sites for vocabulary lists are: