So, following the red line, when you first learn a word (or a piece of information, or anything) if you try to remember it within an hour or so, the memory is pretty good. If you try to recall that fact 6 days later (without any study in between), you'll see (by following the red line to day 6) that the memory for such facts can swiftly decline pretty quickly.
There is a way to avoid this, though, which is something called spaced repetition. Because this half-life or rate of decline of memory is predictable (i.e. everyone has this curve, and how quickly it takes you to forget stuff is more or less stable/calculable), if you remind yourself of the word or fact within certain times, then you will be able to 'reset' the forgetting curve. The great thing about this 'reset' process, is that each time you do it, it takes longer to forget.
For example, let's say you learned the word for mumill just now. You'd ideally want to recall that word 30 minutes after you learned it. Then an hour later, then 3 hours later, then 6 hours later, then 12 hours later, then 24 hours later, then 3 days later, then 1 week later, then 3 weeks later, then 5 weeks, then 2.5 months etc etc).
So if you keep catching the words at the point just before you forget them, you can steadily put the fact/word deeper into your long-term memory.
But, you may ask, how do you remember when the last time you tested yourself on a particular word? How do you ensure that you catch this 'forgetting curve' and know how far along you are with memorisation...
Luckily, a bunch of people have already taken care of this and thought it through, and there's a piece of software which will save your life. I wish I'd had it when I was learning languages at university.
It's called Anki, and you can download it here. They've just released version 2.0. It's free. There are other imitations, but Anki is really the gold standard here. Don't bother looking around. Anki is the real deal.
So with this programme you create a 'collection' of words. You have to input your vocabulary (just one side -- i.e. just Arabic-English or English-Arabic) into the programme. Once one person has done it, then you can share the decks of flashcards (either online or as offline files), so you can immediately become the most popular person on your course if you do a full collection for your course, I would guess. (For more obscure languages, and I include Pashto in this pantheon, there are some true heros who assemble vocabulary lists and upload them to sharing sites for others to use).
Anyway, once you've inputted the cards, it will test you on the words in both directions (i.e. Eng-Ar as well as Ar-Eng) automatically.
Then you just start learning. You can state how many new words you want to learn each day. I'd recommend no more than 20. And, IMPORTANT POINT, you should do steps 1 and 2 (as I explained above) BEFORE you do a round with Anki. i.e. first do the word association stuff, then do a day learning the words with the lists and the blank piece of paper and the columns, and then the next day you should learn those words in Anki. It'll auto-test you the words and you pick an option whether the word was easy to remember, hard, very hard, or whether you didn't remember it at all.
Depending on which option you pick for each word (when you see the answer), it'll then remember which forgetting curve to assign to the word, and it'll remind you that you need to review that piece of vocabulary/fact at the appropriate time.
So let's say in 1 month from now, the word mumill shows up on the screen, and you eventually remember it, but it took a bit of time. You press 'very hard to remember' and it'll remind you of that word in 18 days (approx) since it recognises that you need a bit more time before it really ends up in your longer-term memory.
Then once you've started with Anki, you just have to make sure to return to Anki once a day and study the words that show up for review. Luckily there is a mobile version of Anki available (for iPhone/iPad as well as Android). I'll assume you have a phone which is either an iphone or an android. The mobile versions you have to pay for. But it's completely worth it.
This means that whenever you're stuck in a bus, or waiting in a queue or something, you just need to pull out your phone and you can review a few words on Anki. It has all the same features as the desktop version (apart from the ability to add words, I think). It's also a good idea to include audio along with each vocab entry which will be another sensory association and input that will help imprint the word in your mind.
The trick here, and it's really important, is to do it every day. If you only do it once a week, then you'll forget words more often (as the forgetting curve means you'll have missed the chance to reactivate or 'reset' the curve on words during the week). I really strongly recommend you do your Anki words once a day. Some days there won't be any words, or very few (depending on how many your course has you learning).
4. (Writing/Reading for Extra Imprinting)
If you really want to get to a high level in your vocab learning, then use it to support your more general skills. i.e. you should use the vocab words in context.
When I use Anki, I sometimes like to take each word (when it comes up on the screen for testing/study) and before I give my answer, I first make myself use that word in a sentence. This allows me to practice grammar structures, and also creates new associations for that word with other pieces of material. (For the memory, more associations are better, since things are recalled via these webs/networks of signals in the mind). Even better, write these sentences down (although by now we're talking study/exercises that take a bit of time, rather than just Anki etc, which would take maximum 20 minutes per day).
The ideal place for practicing your writing is lang-8.com, where you can get a free account. The principle here is that everyone corrects everyone else. i.e. when you put up a few sentences of writing practice, native Arabic speakers (or whatever language) will correct your sentences, but ideally you should correct their English sentences etc to return the favour. It's all free, and done on an honour system, so you get as much as you give etc.
I use it for my Urdu, Arabic and Pashto studies, and you'll usually get a correction for things you post there within 12-24 hours, which is pretty amazing when you think about it.
Another really good way to reinforce your vocabulary is to read a lot. Most of the studies of language study and learning (see last week's post) now agree that 'intensive reading practice' is the best way to build up your vocabulary. Obviously, you need to start with texts that are somewhat comprehensible and then slowly build up, and it can be really difficult. Sometimes you think that you're just reading gobbledegook. But slowly, if you stick at it, weeks later, you'll be able to read more and more, and you'll be learning words without the need to memorise and go through all the systems above (although if the word's giving you problems, or if you'd really like to remember it, then by all means add it to Anki etc) because you'll be using and seeing that word in the context of the sentence / words around it etc.
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Anyway, none of this is a substitute for the somewhat-hard work that goes into learning vocabulary, but it certainly can shortcut things. Particularly if you start inputting your vocabulary into Anki early on in the course of your language studies, and reviewing it every day throughout the year, by the end of a year you'll be in a really good place compared to others.