Spaced repetition: Never forget vocabulary ever again

Spaced repetition: Never forget vocabulary ever again


In today’s post I want to share with you a technique I started using that has totally transformed my vocabulary learning approach!

SRS: Spaced Repetition System

SRS is a presentation method that gives you the information before you would forget it and makes sure that it stays constantly fresh in your mind. So, you might see a word a few minutes after the first time, then a few days later, then a few weeks later etc. always at the time you need to see it most to make sure it is constantly fresh in your mind.

It’s a more complex version of the flashcard system where you have a word on one side of a card and its translation on the other. You look at the word, test yourself to see if you know it and turn over the card to see the translation. You couldn’t get more low-tech than that even if you tried, but SRS uses 21st century technology to make this possible while considering the time dimension.

So how would a guy like me who hates studying indoors, definitely dislikes flashcards and already has a pretty good learning strategy, be interested in software for improving recall of vocabulary?

Finding the time to study

Like many people, I’m a busy guy! I’m trying to work, write a book, dramatically improve my level of a language, have a social life and grocery shop/clean/sleep/eat/write blogs & e-mails/exercise etc. every day. But there are ways to make time – get it back from the time spent waiting.

Note: the next paragraphs are taken from the Language Hacking Guide

You wait for the bus/metro/train to arrive, you wait in it while going to work/school or home, you wait in the supermarket queue/line, you wait in a traffic jam in your car, you wait when ordering coffee in the morning, you wait for your water to boil if you prepare it yourself, you wait for your friend to arrive, you wait at the doctor’s/dentist’s, you even wait for a minute or two in lifts, elevators, at traffic lights, when waiting for something to load on your computer, for someone to answer the door after you knock etc.

In most of these situations you may be alone – so if you can’t talk to someone, what do you do? Stare into space? Read advertisements around you? Twiddle your thumbs? Press the pedestrian cross or lift button again in frustration that nothing has happened yet? These little segments of our day fly by unutilised and actually add up to a huge amount of time wasted. You can’t avoid these situations – they are natural parts of your day.

For most people, these little segments are annoyances – why is the other person so late? Why does there have to be so many people ahead of me in the supermarket? Why did my computer have to crash to be rebooted now of all times? Waiting in frustration is simply what we end up doing – considering how much time per day we spend doing this, this is an unneeded source of stress!

I actually don’t mind when these occasions arise! Seriously – if someone is arriving a little late, or if I just missed the bus and the next one won’t come for 15 minutes, or the Internet goes down and I can’t work – rather than cursing at my “bad luck”, and adding stress to my life by being angry during this time, I think to myself – great! Another chance to study some vocabulary!!

Improving on the old-school method

For several years, in these situations I would take out my phrasebook, or pocket vocabulary book for these moments, open it up to a random page and learn whatever I saw. Sometimes I’d see a word I never did before and sometimes I’d see something I needed to review and had already long forgotten and need to relearn rather than just remind myself. It did the job but to be honest, in retrospect it was inefficient and sloppy. (Although, if you learn by listening, these moments are good times to take out your MP3 player and press play!)

Randomly or even systematically going through vocabulary in order like this means that you might not review the hardest words when you need to, or you’ll keep seeing the easy words too often, or you’ll forget words because you didn’t review them for a very long time.

SRS answers all of these issues by letting you decide when you should see a word again based on certain criteria (usually, how hard you felt it was). So the easy words are pushed way off into the future, the hard ones keep constantly reappearing until you are finally happy with them, and the middle-difficulty ones will reappear just when you need them most, to refresh your memory.

Deciding when to study a word again when you see it in a printed list is too hard, but that’s where technology comes in!


Anki is an application developed by Damien Elmes for reviewing things you need to learn, using SRS. Not just vocabulary, but city/country capitals, medical terminology, a script for a play etc. Anything you need to apply to memory really!

It’s a completely free download (or low-bandwidth website) and works on Windows, Mac, Linux and even on mobile phones!

On the surface, the program does more or less what you would expect from a flashcard – it shows you a word with no translation (the word can be either in your native language or in the target language) and you can decide if you know what it means. Then press “Answer” and it will show it to you.

If you thought it was super easy, press the button on the right (which includes a distant time factor, depending on how you reacted to the word in previous attempts), if you had absolutely no idea press the button on the left (it will reappear very soon), and otherwise press one of the other buttons. I like having 4 levels to decide how “easy” I thought it was, and I use each one accordingly.

If it sounds drastically simple, that’s because it is! The most important part of the interface is actually pretty much just that (as you can see on the iPhone screenshot I took; similar on other systems) – the impressive part of all of this is actually the algorithm working in the background to decide precisely when to show you the words.

You don’t really have to think about that aspect though, since the system covers it for you. All you have to do is think about the word and then grade it on difficulty (hardest one if you’ve never seen it before).

Using the program

There are broadly two ways to use this application and they depend mostly on the resources available to you. Everyone can use it for free on their computer, and you can simply decide to devote 30 minutes a day to using it and make sure to set aside that time every day.

A huge amount of people have been recommending this program to me since I started this site, but I dismissed it as “not for me” without really trying it, because of how I dislike flashcards and generally don’t like sitting down to study. If you have that focus, you will get a lot of use out of this program!

Based on the time-wasting description above, you can guess where I do my studying! On the go! You can see in the post’s main picture that I even swipe it out for 2 minute waits before crossing the road!

I happen to have an iPhone (invested in it just before my laptop broke and replacing it meant I suddenly couldn’t afford to have bought an expensive Apple device, and still can’t, but that’s a sob story for another day) which is jailbroken, but if you have an Android device or Nintendo DS you can also use Anki offline (no Internet access required). If you have any other portable device that can access the basic webpages (modern mobile phone, Palm device, Sony PSP etc.) either by wifi or 3G/Edge (mobile phone network), then you can use the Anki system that way too (on a very low bandwidth website).

The way I did this was as follows: Install Anki on your computer, then download “decks” of prepared vocabulary sets to study in the language you are working on (on the Decks screen click Download – there are lots already waiting for free download!). You can also prepare the vocabulary yourself based on words you want to study, as explained in this video. If you don’t have the right mobile device, then stick to this computer interface and use it to study the words whenever you have time. Its use is pretty self-explanatory, but here are some videos of how it works.

If you can make it more portable, next thing to do is to create an account on Ankionline and then to synchronise your computer’s Anki with the online version (File –> Sync). Then install Anki on your mobile device and synchronise with the same account (you only have to necessarily do this once, then just use your mobile device and ignore the computer version until you need more material to study). If you don’t have the particular devices that allow for offline access, but can access the Internet on your mobile device, just go directly to the Ankionline page and use its low-bandwidth interface to learn from.
The set-up takes a few minutes but then you just have to open the program and use it whenever you can! All the little minutes add up very quickly. Since I haven’t found some websites too helpful for learning vocabulary, I’ve done most of my “studying” over the last weeks in Berlin’s U-Bahn, on buses and in cafés/supermarkets etc. without ever carrying any books with me!

SRS must be used with other learning strategies

Despite how obviously enthusiastically I’m sharing this system with you, it is important to be aware of the fact that it is just one way to acquire new vocabulary. The best way by far is to hear and apply it in context with native speakers. Even if you “knew” all the vocabulary in the world you still wouldn’t be able to actually apply it in actual conversations if you didn’t work on other skills important to language learning (which I discuss a lot in the Guide).

Since you are usually hearing words in isolation (although it’s possible to include example sentences), it means you have no context and this is quite an artificial way to learn words, as simple translations of something from your mother tongue, rather than understanding how to use the word itself. You can’t learn any language just by learning translations. Someone using too much SRS would not necessarily be any further along compared to someone using other strategies.

On top of this, just looking at the word is not enough and SRS can turn into nothing more than a fancy version of rote learning by pure repetition if you don’t think harder while using it. If you are exposed enough times you will be forced to remember it, but what I prefer is to try to make an image association of the word and/or to think of an example to use it in and say that to myself, so that I use it in its right context. This way I’m much more likely to remember it next time.

SRS by itself is far from perfect, but if you use it while thinking independently too, its potential is much greater. I’m sure lots of you know the feeling that you have learned a word, and you are sure of it, but you just can’t say it. This may simply be because it’s been too long since you reviewed that word, and using SRS a few minutes a day will make sure that all words you use in the system will never be neglected if you use it right.

Another thing to take into account for learning words efficiently and avoiding forgetting them is to avoiding learning the vocabulary only one way: foreign language to native language, focusing on recognition rather than production. This focus means a lot of people understand languages but are at a loss when the time comes to speak them. In this case, it’s important that you see words appear in SRS for translation to the foreign language too.

When used on a computer, you can acquire single-word vocabulary very quickly (it works easily with the keyboard 1,2,3,4 & space keys for quicker navigation than with the mouse) if you set aside 30 minutes a day to review words. And in its mobile form you can take advantage of time that you would otherwise waste, to improve your vocabulary!


I interviewed the Anki developer Damien as part of the audio for the Language Hacking Guide, to understand SRS better, and he is going to continue to develop different versions of this open-source software for people to enjoy. Give it a try!

If you have experience with Anki or other applications that apply SRS let us know! Has it helped, or do you prefer other systems for vocabulary? People also use it for learning scripts such as Kanji, and you can add audio and pictures if you feel that would help!

Wish me luck for Monday! I’ll have an extra bonus for the first people to get a copy of the Guide. I’ve been working for about 6 weeks full time total to produce this and share it with the world! You can see that I haven’t been posting regularly to the blog because of that, so hopefully that will change soon! I’m looking forward to releasing it into the wild :)


Enter your email in the top right of the site to subscribe to the Language Hacking League e-mail list for way more tips sent directly to your inbox!

If you enjoyed this post, you will love my TEDx talk! You can get much better details of how I recommend learning a language if you watch it here.

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