This approach is quite interesting because it’s actually not about trying to remember words by making lists or any such thing; memory, does not work by using intentional effort (David James also talks about it). If you “try” to remember new words multiple times, you will spend lots of mental energy just to put the information into your short-term memory. Of course, such an information will not be stored for long. Usually, information stored in a short-term memory and it won’t stick for more than 2 weeks.
Another statement from David James says, that the reason many linguists thinks that kids under the age of 5-6 learn languages that well is because they learn unconsciously. Everything that happens after that age is a sort of an “extra layer” which builds further as the child becomes a self-consciously learner. By school age, we aware that “now we are learning something” and we make some efforts to remember. This is why the short-term memory becoming more and more involvement, blocking the long-term memory function critical to the easy learning of languages.
This method is also about learning through context and using ‘back and forth’ translation exercises. Learning through the context by reading as much as you can, and by being emotionally engaged with what you are learning (i.e. something that you find interesting and that you are really passionate about). Finding a word in different contexts will boost your capacity to remember new words, this is why reading as much as possible is a really good way to memorize
With the ‘back and forth’ translation method, you read a bilingual text (a dialogue, for example) and try to translate the sentences back and forth into your native language. After having initially read a text, you go through it once again in the target language, and this time, don’t look at the translation, try to translate the text back to your native language and then check for mistakes. Get back to the translations a few days after and try to translate it back to the target language. This way you force yourself to convey a message. In fact, the words “stick” as a consequence of wanting to say something.
With this method, memorizing new vocabulary will come naturally as a consequence of being exposed to material in the native language, by being interested and passionate by the content.