How Many Words Should You Learn A Day In A Foreign Language?
So spaced repetition apps like my app Litany make it very easy to change how many new words you learn a day. Because they don’t rely on structured lessons. They use an algorithm to teach you new words with flashcards. This allows them to show you words right when you’re about to forget them leading to a significant increase in recall.
But if it’s so easy to set the number of new words you learn a day what number should you set? So the answer will actually vary a little based on how much free time you have but I think most people should be aiming to learn at least 14 new words a day. And here’s why.
Learning New Words Is Not Linear
So how did I get to this 14 words a day figure? Well, first I’d like to talk about my experience with Anki. So I installed a deck and by default it gave me 20 new cards a day. And each card had either a phrase in English and Mandarin Chinese. And there were two cards for each phrase: a Chinese on the front English on the back card and an English on the front Chinese on the back card.
So 20 cards meant I was seeing 10 new phrases. And some phrases contained multiple new words. And some of the words were pretty obscure to be honest. It’s why I made Litany.
So 20 cards a day was a lot. And my review sessions were actually quite long. So I thought I’d cut my review sessions down by reducing the new cards per day.
And this is actually where I made a very important observation. Let’s say I was getting like 40% of the cards right after just one review in the 20 cards set.
A bit of a side note: when you don’t successfully remember a card you press ‘again’ on it in Anki and it will show up again later. This feature also carries over to Litany.
But of course you almost always have to press the again button once because you’ve never seen the word before. So how it works is Anki, and Litany, will show you the card on day 1, day 2, and then in exponentially increasing intervals assuming you got the word right. If you didn’t get the word right it’ll start the whole process again. So you’ll always see the card on day 1 and day 2. The other days? Who knows. Although I think Anki has a way of skipping it if the card is easy enough. So, yeah, I’m talking about hitting the again button on day 2.
So when I say I was getting 40% of the cards right it means I got 40% of them right on the second day meaning we start on that exponential curve. The other 60% get reset back to day 1.
So back on the story, 40% accuracy for 20 cards means I was able to press again once for 8 cards. So I expected once I dropped the number of cards down to 10 from 20 the accuracy would go up to 80% (so it’s still 8 cards).
But this wasn’t what ended up happening. Instead the 40% accuracy stuck meaning I was now able to press again once for only 4 cards.
It’s a bit surprising. Of course the cards I got wrong are harder, but I expected that having to remember less would increase my ability to remember.
I guess in hindsight it’s not too surprising but I was surprised when I noticed this the first time.
So this means that your memory doesn’t really have a fixed capacity of new words to learn each day. It’s more of a sponge that sucks in new words at a fixed rate.
In economics terms we’d say the number of new words you learn is elastic.
So What’s Stopping You From Learning 100 Words A Day?
Well, I guess you could. People like Tim Ferris actually talk about doing this. Just dump hundreds of words into your brain in a single day.
Although I’ve never tried this myself. I suspect you’d really have to bring your mnemonics A game if you want to try this.
But there is another reason you wouldn’t want to go this fast. And that’s the problem I encountered with Anki: the review sessions end up becoming enormous.
Now, my app Litany actually does some clever things to reduce the number of reviews. It’s smart about the words. It knows that if a word occurs in a phrase you don’t have to review a word again as well as some other optimizations.
Although these optimizations only get us so far. In Anki you’d expect the number of old cards to review to be about 7x your new cards. For Litany it’s about 5x. I expected better but oh well.
So that means if you study 100 words a day you’re going to be looking at reviewing 500 old cards on top of your 100 new cards so 600 total. I actually put a feature in Litany to track my review times and it is telling me that the average amount of time to review a card for me is about 15 seconds so that’s about two and a half hours of review time. Now if you have a lot of down time go ahead. But I think the majority of us would like to avoid review times that are that long.
How Many Words Do You Need To Learn A Day?
Often in these types of questions it’s useful to work backwards from the solution. How many words is ‘good enough’? The number varies but I think a good enough number of words that you have to memorize is 10,000. This is going to make you sound ‘fluent’ in a language (although I argue the term fluent shouldn’t really exist).
Some people say you need as high as 15,000. Some people say you need as low as 5,000. I decided to just split the difference and say 10,000 is good enough. It’s probably not going to make you sound better than a native speaker but you aren’t going to be constantly tripping over your words either.
Then the next thing to do is calculate your time scale. How much time do you want to spend learning a new language? And for me the answer is obvious. 2 years. When you look at polyglots they often say they take 2 years to learn a language comfortably.
Now there are some ‘gurus’ that say you can learn a language in a lot less. But for the most part what the gurus are selling is just the ability to say a few basic words. Not what you want.
So now we have 10,000 words we want to learn and we have 2 years or 730 days. Now you just divide the two numbers and you get that you have to learn 13.69863 words a day. Rounded up that’s 14 words a day.
Of course this is assuming you study every day which you really should.
What I Do
So in Litany I am currently studying two languages: Mandarin Chinese and Spanish. I had previously tried learning German at the same time but I got mixed up between German and Spanish so I dropped German.
Mandarin Chinese is not a very high priority for me so I’ve actually set it to only 5 words a day. Spanish, on the other hand, I’m studying at 14 words a day.
Also keep in mind that in Litany when I say ’14 words’ it’s also possible for us to study more than 14 words a day. This is because the algorithm incrementally builds up the phrases to learn. We may be at 13 words and the next phrase has 2 new words. So rather than not learning the new phrase I just include the 2 word phrase so we end up studying 15 words.
