A recent article on this blog mentioned that a vocabulary of around 3500 words is enough to get by at B2 level. Given that most learners take at least five years to reach this level, that means they need to acquire about 700 words a year, approximately twenty words a week during the academic year. This seems like a fairly modest accomplishment, but still one that many learners fail to achieve.
One reason for this difficulty is that students waste time learning words that aren't useful. But the main cause of failure is that the words are forgotten. Unlike grammar, vocabulary is particularly easy to forget - whereas grammar builds up into a system of interrelated knowledge, vocabulary tends to be memorised as individual items. And it is estimated that if learners only have a single exposure to new vocabulary, 80% of it will be forgotten within a few days.
This indicates an obvious solution - we need to recycle the vocabulary in subsequent lessons. Taking a few minutes at the start of each lesson to review the words learned in the previous week can make a tremendous difference to retention rates. Over the next few weeks, we'll be posting on this blog lots of suggestions for quick activities that you can use to recycle new vocabulary.