Which Words Should ESL Teachers Focus on First 

Since some words are so rare and knowing them will not make a big difference in understanding written texts, recent research has suggested that it is better for learners at the beginning of their second language acquisition journey to focus on learning the most frequent words first and then move on to acquiring the vocabulary related to their interests and needs. The focus of lexical research on beginning ESL learners is not on average vocabulary size, but on learning the "right words".

Lexical studies suggest that some words are more frequent than others, therefore more useful for second language learners. Decades of corpus research and the advent of online text databases motivated some researchers to focus on identifying the most frequent words that are necessary to understand a written text. Francis and Kucera (1982) suggest that the 2000 most frequent word families of English make up 79.7% of the individual words in any English text, the 3000 most frequent word families represent 84%, the 4000 most frequent word families make up about 86.7%, and the 5000 most frequent word families cover 88.6%.

By knowing the 2000 most frequent word families of English, readers can understand approximately 80% of the words in any text. Therefore, the goal of an English learner should be to acquire these 2000 word families first, since this relatively small number of words is recycled in any piece of writing and ensures the basis for reading comprehension.

Acquiring vocabulary at random does not necessarily ensure that the most needed and frequent words are learned before less frequent and useful words. Cobb (2007) suggests the fast-track alternative of learning the 2000 most frequent word families from online frequency-based word lists linked to dictionary explanations. In order to simulate rich natural contexts, Cobb's (2007) publicly available computer program displays word lists linked to a software providing concordances, which are authentic contexts for each word, derived from a large collection of texts.

While using computer-provided contexts may not be as powerful as meeting words in natural contexts, Cobb (1997) suggests that "using computer concordances can get the learning process off to a good start". ESL teachers can incorporate the use of lexical concordances in their practice, either by facilitating computer-assisted vocabulary teaching if their classroom environment provides access to online technologies or by preparing printed handouts of concordances for the 2000 most frequent words.

However, knowing only the 2000 most frequent word families or 80% of the words in a written text gives a second language learner only a general idea of what is being said in a text, without ensuring deep reading comprehension. A much better reading comprehension power is ensured if a reader knows the meanings of at least 90% of the words in a text.

Nation and Waring (1997) suggest that by knowing the 2000 most frequent word families, plus the Academic Word List (AWL), a second language reader would understand about 90% of the words encountered in any academic text. There are approximately 570 words in the Academic Word List (AWL) and they are also available online and linked to concordances (Cobb, 2007). After teaching the 2000 most frequent words, ESL facilitators can use Cobb's online resources to address the words from the Academic Word List.

Even if understanding only 90% of the words in a text does not ensure ideal reading comprehension, it is a foundation on which second language learners can build on by subsequent reading, more advanced vocabulary instruction, and exposure to natural contexts.