The approach taken in this book rests on the idea that a well-balanced language course should consist of four major strands (Nation, 2007; Nation and Yamamoto, 2011). These strands can appear in many different forms, but they should all be there in a well-designed course. Firstly, there is the strand of learning from comprehensible meaning- focused input. This means that learners should have the opportunity to learn new language items through listening and reading activities where the main focus of attention is on the information in what they are listening to or reading.
As we shall see in the following chapter, learning from meaning-focused input can best occur if learners are familiar with at least 98 per cent of the running words in the input they are focusing on. Put negatively, learning from meaning-focused input cannot occur if there are lots of unknown words. The second strand of a course is the strand of meaning-focused output. Learners should have the chance to develop their knowledge of the language through speaking and writing activities where their main attention is focused on the information they are trying to convey. Speaking and writing are useful means of vocabulary development because they make the learners focus on words in ways they did not have to while listening and reading. Having to speak and write encourages learners to listen like a speaker and read like a writer.
This different kind of attention is not the only contribution that speaking and writing activities can make to language development. From a vocabulary perspective, these productive activities can strengthen knowledge of previously met vocabulary. The third strand of a course is one that has been subject to a lot of debate. This is the strand of language-focused learning, sometimes called form-focused instruction. There is growing evidence (Ellis, 2005; Williams, 2005) that language learning benefits if there is an appropriate amount of usefully focused deliberate teaching and learning of language items. From a vocabulary perspective, this means that a course should involve the direct teaching of vocabulary and the direct learning and study of vocabulary. As we shall see, there is a very large amount of research stretching back to the late 19th century which shows that the gradual cumulative process of learning a word can be given a strong boost by the direct study of certain features of the word.