I have a theory when it comes to learning vocabulary in a second language that goes like this:

We know that both active and passive learning of vocabulary is necessary. My theory is that each should be as much like the other as possible.

For example, if you’re doing the active vocabulary task of looking through lists, a word list, or a dictionary to learn words, then you should always have an example sentence to review the word in a more passive situation. This helps to provide the vital context needed to truly understand the vocabulary. Just looking at the isolated vocabulary alone is not enough, in other words.

Similarly, if you are reading or listening to something, the text must contain the target words. This second point is made all the more easier through the huge range of graded readers, and now graded listeners available. Being able to separate texts into number of headwords is a huge advantage, in other words.

If you can, when learning vocabulary in a second language, you should try and mix up your learning in these ways. It may be more of a hassle to set up this system, but it will definitely pay off in the long run.

My definition of active and passive vocabulary learning

Active vocabulary learning is when you specifically choose the words you wish to remember, such as choosing them from a glossary, a word list, or even a dictionary. Passive learning is getting exposure to the language be it written, spoken, or otherwise (listening is also seen as an active skill, as when you listen, you respond by letting the speaker know you are listening).