Vocabulary development plays a vital role in making the transition from an intermediate to a more advanced level of language proficiency, but many learners appear to have reached a learning plateau in relation to vocabulary. This may be seen in the overuse of lower-level vocabulary and failure to acquire more advanced-level vocabulary, as well as limited awareness of collocational usage. In terms of the quantitative dimension of vocabulary learning, vocabulary development can be thought of as involving acquisition of a core vocabulary that is common to many different domains, genres, and text types. In addition, learners build up more specialized vocabulary related to their own needs and fields of interests, whether these be academic, occupational, or social. How big is this core vocabulary?

Researchers suggest that knowing a minimum vocabulary of 3,000 words is required to understand a high percentage of words on an average page of a text. This represents a target for the lower-intermediate learning level. Hu and Nation (1992) found that a vocabulary of 5,000 words was needed to read short, unsimplified novels for pleasure, while Hazenberg and Hulstijn (1996) found that twice as many words were needed to read first-year university materials.

In addition to this core vocabulary, there are another 1,000 or so words common to academic disciplines, sometimes referred to as the basis for an academic vocabulary. However, once learners reach the intermediate level, they often fail to make sufficient gains in their vocabulary knowledge. A study of college students’ vocabulary development in China found that during their first two years of university study, English majors’ vocabulary increased by 1,500 words on average each year; but in the later two years, their vocabulary increased on average by only 250 words each year (Fan Yi, 2007).

O’Keeffe et al. (2007) comment:
A receptive vocabulary of some 5,000 to 6,000 words would appear to be a good threshold at which to consider learners at the top of the intermediate level and ready to take on an advanced program. Such a program would ideally have the following aims:

“Knowing a word” of course involves far more than simply recognizing its meaning. Gairns and Redman (1986; cited in Moras, 2007) include the following components of lexical competence:

One of the key problems in helping learners improve their vocabulary is finding effective ways to help them remember words they have encountered. How can we help learners move words from short-term to long-term memory? One clue is from research on memory. Gairns and Redman (1986) point out that our mental lexicon is highly organized and efficient, and that items that are related semantically are stored together. This is why it is much easier to recall a list of words that are grouped or organized in a meaningful way, as compared with trying to recall a set of words that are simply organized alphabetically. Word frequency also plays a role, since the more frequently a word is encountered, the easier it is to remember.

Helping learners develop their own approaches to vocabulary learning is also an important goal at the advanced level, so that learners can deal with new words they encounter in independent learning. Moras (2007) recommend the use of guided discovery, contextual guesswork, and mastering dictionary use as effective teaching and learning strategies.

Guided discovery involves asking questions or offering examples that guide students to guess meanings correctly. In this way learners get involved in a process of semantic processing that helps learning and retention.

Contextual guesswork means making use of the context in which the word appears to derive an idea of its meaning, or in some cases, guess from the word itself (i.e., those familiar with Latin-based words). Knowledge of word formation (e.g., prefixes and suffixes) can also help guide students to discover meaning. Teachers can help students with specific techniques and practice in contextual guesswork, for example, the understanding of discourse markers and identifying the function of the word in the sentence (e.g., verb, adjective, noun). The latter is also very useful when using dictionaries. Students should start using EFL dictionaries as early as possible, from Intermediate upwards. With adequate training, dictionaries are an invaluable tool for learners, giving them independence from the teacher. As well as understanding meaning, students are able to check pronunciation, the grammar of the word (e.g., verb patterns, verb forms, plurality, comparatives, etc.), different spelling (American versus British), style and register, as well as examples that illustrate usage.

Another dimension of vocabulary development, which is essential if students are to make a successful transition to the advanced level, is to expand what has been called their collocational competence. Collocation refers to restrictions on how words can be used together, such as which prepositions are used with particular verbs, or which verbs and nouns are used together. Corpus analysis has allowed common collocational patterns in English to be easily identified (O’Keeffe et al., 2007). Knowledge of collocations is vital for effective language use, and a sentence that is grammatically correct will look or sound awkward if collocational preferences are not used. For example we can say “blond hair,” but not “blond car”; “lean meat,” but not “slim meat”; “perform a play,” but not “perform a meeting.” Vocabulary development does not only involve acquiring new words. It also involves expanding knowledge of the collocational patterns that known words can enter into.

O’Keeffe et al. (2007) comment:
One may conclude that collocations, along with semantically transparent and opaque, idiomatic chunks, form the main component of the multi-word lexicon and that the multi-word lexicon is at the heart of advanced level lexical knowledge, given that the challenge at this level is as much to do with grappling with observing recurrent collocations and chunks (which will most often consist of words already known individually) as it is with simply pushing for a (never-ending) linear increase in the vocabulary size based on single words never seen before (p. 53).

Article from: Richards, J. C., ”Moving Beyond the Plateau From Intermediate to Advanced Levels in Language Learning”, 2008, Cambridge University Press.