Vocab-Building through Associations
The human brain is, in part, a vast network of information. Just like webpages contain links to each other, bits of information (let's call them 'nodes') in our brain are linked to each other. Nodes are closely linked if they are pieces of knowledge that were learned together, or memories that were formed at the same time and place. The further apart any two nodes were formed (in terms of time, place, significance, or other context), the less direct their connection is (e.i. they'd have to connect to a number of other nodes in order to reach each other).
The connection between nodes is important for memory. The closer any two nodes are to each other, the easier it is to remember one after thinking about the other. On top of that, each time you call upon any association between two nodes, their connection strengthens, making it easier and more natural to recall them in the future.
Teachers should keep this in mind because the way a concept is taught affects how the students understand it. Associating something new with something familiar will make the new concept easier to grasp. That's why teachers are encouraged to teach within contexts that the students already know and appreciate. It's also why I use a consistent color scheme. Similarly, the way students learn affects the way they remember (i.e. the way they establish nodes affects the way they call upon node-connections); things learned together are more likely to be remembered together.
This principle is great for vocabulary acquisition. There's a reason books teach vocabulary in groups. For example, you might teach fruits this week, jungle animals next week, and places in town the week after that, instead of teaching one thing from each category every week. So if a student is struggling to remember 'tiger', she might recall it after thinking about 'hippo' and 'snake'.
Thankfully, books tend to put vocab into groups for us. But inevitably, we revisit vocab - or even teach new vocab - out of the book's context as the need arises in the classroom. When this happens, try to form associations for your students. You don't need large groups of words; pairs or trios often work best.
Here are some types of associations I recommend:
Opposite Adjectives - fast and slow / loud and quiet / small, medium, and large, etc.
Opposite Verbs - open and close / smile and frown / come and go, etc.
Partnered Verbs - walk and run / sit, stand, and lie / eat and drink, etc.
Partnered Nouns - hat and gloves / dog and cat / mind, heart, and soul, etc.
Common Noun-Verb Pairs - my tummy grumbles / pencil and write / lock the door, etc.
Degrees of Adjectives - cold and freezing / good, better, and best / tired and exhausted, etc.
Irregular Verb Forms - sing, sang, and sung / catch and caught / draw, drew, and drawn, etc.
Irregular Plurals - child and children / cactus and cacti / person and people, etc.
Be careful with synonyms, though, because either students can find them confusing if they don't understand the distinction, or they'll see no reason to remember both words.
The examples here are rather elementary, but you'll certainly have the opportunity for different ones at a more advanced level. In any case, when teaching a new (or old) vocab word, try to think of another word or two that often goes with it.
Hopefully, forming associations will improve students' memories. Instead of trying to directly remember one specific thing, they can succeed by remembering a related thing (an opposite, a pair, etc.), which would then guide them to what they're looking for.
Even if students don't end up remembering whatever word they want to use, they can still convey what they want to by stating a related word ("The film was very, um, not 'boring', what's the other word? Yes, 'interesting', that's it!"), and perhaps another English speaker can help them out. Either way, leaning through associations can improve communicability.