Many, many years ago, when I was first trying to master a series of foreign languages, it didn't take me long to notice that you never really own the things you study. Set it aside for awhile, and it fades away.
So Version 2 of my method was based on constant review. The drawback to this approach is that if you commit, for example, to spending 15 minutes a day on review of each language you study, by the time you get up to four languages you are looking at a pretty serious ongoing time commitment. And as for eight, or twenty languages....
So with Version 3 I was driven to discover the principle of spaced repetition (though I was by no means the first to do so). To wit, if you want to commit to remembering a given fact in perpetuity, you indeed have to be prepared to review it infinitely many times, but each after each successive review it sticks in the mind a little more firmly, and you can let a longer interval go by before reviewing it the next time. Thus on average, you spend less and less time each day maintaining your memory of a given fact.
My implementation of this system consisted of a series of stacks of index cards ("flash cards") for each subject. (This was in the days before you would think of having a computer in your house.) The first stack of cards was reviewed every day. Once I felt pretty good about a card, I would move it to the second stack, of which only half was reviewed every day (so that on average I looked at each card with a one-day delay). If I got a card in the second stack right, I moved it to the third stack, of which I reviewed only one-fourth of the cards each day. Otherwise, it bounced back to the first stack. And so on the fourth stack, the fifth stack, etc. In some cases I had up to nine stacks, Once a card made it to the ninth stack, it would take 512 days before I saw it again. (Update: I have learned that this is called the Leitner system.)
This principle of reviewing over and over and successively increasing intervals is known as spaced repetition.
I despoiled thousands of index cards. I had boxes and boxes full of them. Once I got my own computer it didn't take long to see the advantage of going paperless (or cardless), so I wrote my own simple spaced-repetition program (nowadays people use "SRS" to refer to spaced-repetition software). My program had no editing—I used a separate text editor with a text-based file format of my own devising—and could only handle content in the Roman alphabet. So Chinese, Arabic, etc. were still based on hardcopy index cards. I did use my program for Sanskrit, but only in transliteration.
Which brings me to the subject of this post, which is a little program called Anki. "Anki" is the Japanese word for "commit to heart." I have been using Anki for almost a year now, and have found it extremely useful.
Truth be told, I had heard of Anki for some time before I got around to trying it. I think I had low expectations because I was projecting the limitations of my own little program onto it. But where my little program was a slingshot, Anki is a multi-warhead smart missile. It uses a sophisticated formula to decide when to present review material, based on your level of confidence when you review a given fact. It handles any kind of text that your computer will handle: Chinese, Japanese, Thai, Arabic, Tibetan. It handles pictures and sounds if that's what you want. And the price is right—free.
More features of interest: if you have a smart phone (I don't, but that's a topic for another post) there are versions of Anki that run on the popular smart phone models. There is also a Web interface. So you can sync your review materials to the Web and then use the Web interface to run Anki from any Web browser (I do this on my Nook). You have to go back to the client application for most options, though, and to do serious editing of your database.
A button brings up a set of graphs showing how much time you spent studying per day for the last month, or last year, or whatever; how many cards; success rates; etc. I find this very useful for managing my studying. I have found that carrying out a spaced-repetition study program is like piloting an ocean liner—takes time to get moving and takes time to slow down. Of course you could just drop it and go back to watching Real Housewives, but the whole point is to avoid doing that. So use caution in ramping up too quickly—each new card is a lifetime commitment.
Another valuable aspect of Anki is the ability to share decks (a single study cue is called a "card" and a collection of such is called a "deck"—the analog roots of this method are obvious) on-line. So there is a sizeable library of source material out there that you can download for free. You can then edit it to suit your own predilections. The selection is impressive—I found decks for such relatively obscure subjects as Tibetan and Akkadian.
Recently Version 2 of Anki was released and I made the transition to the new version. It was the usual story with software updates—a lot of things fixed that didn't need fixing—but I found one new feature that justified the growing pains. The new version offers native support for images and sounds on the Web platform. In other words, if you want to include pictures and sounds in your flashcards, you can upload them to your Web account and then access these as well using any Web browser. With the previous version, you could do this only by employing a third-party service. This is important to me because the ability to use pictures means that no script is too exotic to interface with. Just scan a page from your book and (digitally) clip out the parts you need (or you can find plenty of already-scanned books for free on-line). This is the approach I use for Sumerian, for example, or in working through Piggott's 1912 book on Japanese calligraphy. In the latter case, my cards consist entirely of images--a cursive written character on the front and a more prosaically written version of the same character on the back (as in the picture above).
I've been using Anki now for almost a year, and I can't imagine that I would undertake the study of any academic subject (not just foreign languages) without creating or downloading an Anki deck to help through the memorization part of the task. Do yourself a favor and try it out. Anki is available here.