It's not uncommon that I come across a leech while studying my Anki cards. Usually this is the result of confusing two similar items (vocabulary terms, IPA symbols, whatever).

Once I've identified that I'm easily confusing two "similar" items, how can overcome this problem?

Some thoughts I've had:

  • Spend some time studying the two terms in greater depth, to build a stronger memory around each item.
  • Develop a mnemonic to differentiate the two.
  • Study only one for a while (a month?), then introduce the second one after the first is reasonably well mastered.

Each of these has potential drawbacks in my mind. What techniques have others used with success?

7 Answers 7


I'm going to go through how I learned to differentiate between the Japanese Hiragana characters "れ" ("re") and "わ" ("wa"). The only difference is that "re" has an outward hook at the end of the rightmost stroke, whereas "wa" continues inward.


Duh. Just keep working. But, the nature of a "leech" is that practice just doesn't seem to work. You try over and over again to pound those terms into your head, but they bounce right off, like... bouncy balls off pavement. We need something soft and sticky, like gum, not springy rubber toys!

Change Study Habits

This is the obvious next step. We have to change things up! Change is good for your brain. And your wallet.

I'd do practice sets with just the "r" sounds: "ra", "ri", "ru", "re", "ro". I was easily able to identify the "re" sound, then, but when I'd go back to practicing every character, I'd mess it up again. I'd mess up less (so it helped, a bit), but I'd still mess up. Bleh.

Okay, what's next?

Change Study Habits


If you're working with Anki flashcards that go term -> meaning only, you're only getting half the benefit. Now, now, don't go just meaning -> term only, either! Do both simultaneously (use the "Basic (and reversed card)" in Anki)!

Aw, man! I'm still making mistakes? What now?

Change Study Habits


This is the one that cinched it for me: practice just "re" and "wa"... and go fast! Go as fast as you possibly can! Don't worry about mistakes-- just go fast. Of course, this initially just led me to look for the direction of the hook at the bottom of the character. That's not bad, but when studying other characters along with these two, it could cause some problems. Solution? Add more characters. Slowly. But still go fast.

The thing is: don't stick to just one method. Keep changing it up!

Obviously, the study method that worked for me, I guarantee is not going to work the same for you. Experiment, change your study methods often.

EDIT: If all else fails, write an answer on a StackExchange site detailing your problem and your attempts to solve it. It can help more than you know... ;)

  • 3
    Did I also mention change study habits? Commented Apr 6, 2016 at 20:25
  • Very detailed answer! This could be the basis for another question about overcoming plateaus in language learning. Commented Apr 6, 2016 at 20:27
  • @callyalater Thanks! Ya know, as they say: "Consistency is key." Oh wait... :)
    – Hatchet
    Commented Apr 6, 2016 at 20:28
  • write an answer on a StackExchange site detailing your problem I don't understand, write a question... or ... detailing your solution?? Commented Apr 8, 2016 at 0:17
  • 1
    oh :/ ok.. jokes are hard I guess. Commented Apr 8, 2016 at 0:21

There are several things you can do to overcome leeches for words or phrases that are somehow "similar".

Separate the confusing items in time

Instead of keeping both cards in your Anki deck, so they can pop up in the same session, remove one of them until you have thoroughly mastered the other one. This strategy is inspired by my first teacher of Chinese, who first only taught us the negator 不 (bu, which is used for most Chinese verbs and for adjectives) and only later taught us the negator 没 (mei, which is used for the verb 有 - to have - and a few other cases).

Make the flash cards more "memorable"

If you are using plain text flashcards, make the cards more striking by adding relevant images or even sounds. You can also use colours for specific aspects (e.g. for grammatical genders, etc.), as recommended by Gabriel Wyner in his book Fluent Forever.

Vary the types of flashcards

In addition to simple translation flashcards (by the way, Gabriel Wyner says that you should avoid translations to learn vocabulary) and image-based flashcards, you can also use cloze tests to learn/test your vocabulary. (I think the "cloze test" template is one of Anki's default templates.) Of course, you can also use colours and images on flashcards with cloze tests to make them more "memorable".

Finally, flashcards should not be your only method to learn vocabulary. You should also get "comprehensible input" (see Stephen Krashen's language acquisition theory) through reading and listening.


I was working with my 7-year-old on spelling and he was stuck on the word "while". One day I said let's use a song to memorize "while". So we came up with a quick song and spelled the word to the song.

After about two reviews it clicked and he no longer missed this word.

The moral of this story is that sometimes we need to approach learning using different learning styles. Maybe you don't use music much, but it's a powerful tool to apply to a leech.


The safest way is to "[s]tudy only one for a while [...], then introduce the second one after the first is reasonably well mastered."

Lets imagine while learning English you are having trouble learning 'their' and 'there': you realize that you are confusing them, and maybe they even end up as leeches. First you suspend one of them, and for the other one you add at least one new card every day, each time using that word in a new short sentence. So if you suspend 'there' and keep 'their', then one day your new sentence might be "their trousers are black", the next day "my friends came with their kids", and so on. Of course you should add cards with other words as well (stick to your usual number of new cards a day) and you should learn them all together in your regular English deck (i.e. you don't want to end up with only 'their' cards). When you've really learned that one word well, then you "un-suspend" the other one. This way you give your brain the chance to really build up a strong connection between one word and its meaning, before adding a conflicting similar stimulus.

Avoid typical textbook exercises like "'their' or 'there' - fill in the blanks" (i.e. where you have to choose between the two) - these only strengthen the confused pathways between those similar words in your brain. After all, your main goal is not to learn to consciously choose between those two words, but rather to establish a really strong connection between each word and its meaning, so that in a regular conversation--where there will be no time to think--you will subconsciously pick the right word.


Me personally, I study the two cards in my free time and try to locate their differences in each other.

I use my free time as a time to study, allowing myself to take in as much information as I can without pressure (or going too fast). By locating the differences per card, you can put less info into your brain and thus learn them quicker. Though this might consume most of your free time for like a week or two, you will soon identify your cards faster.

If that doesn't seem it is going to work, talk to yourself when you are alone, explaining what each card is and their differences over and over. Even try to use them in sentences, with the appropriate word. This is great when you have a lot of time to yourself.

And if that doesn't work, try changing the way you study, fooling your brain a bit. That usually helps as the same old ways of repetition gets boring and more boring and I don't learn anything.

  • Good point about identifying differences. I have noticed this when focusing on Chinese Characters. Commented Apr 6, 2016 at 20:22
  • When you say, "I use my free time as a time to study", I assume that studying here refers to reviewing flashcards?
    – Tsundoku
    Commented Oct 12, 2018 at 12:13
  • Yes @ChristopheStrobbe Commented Oct 12, 2018 at 21:21

Create a rule by which to remember the correct answer and then practice

  1. You need to recognize the leech exists. Anki will help with this.
  2. Come up with a method of remembering the correct answer. It can be very slow, awkward and personal; it does not matter. If you are confusing two objects, come up with a rule with which to recognize at least one of them; then you can check if the object you are trying to identify satisfies it, and if not, it is the other one.
  3. When you meet a difficult object, use your rule to identify it, no matter how long it takes.
  4. After sufficient practice, you will start to get a feel for the difficult objects. Notice your guess, but check with your rule.
  5. With sufficient practice, you will get confident that you do remember correctly, and will only have to check rarely. You are done.

This worked for me when learning the japanese kana.


It is possible that one of the reasons that leads to leeches is the tip of the tongue phenomenon:

Have you ever been asked a question that you know the answer to, but found yourself struggling to think of the correct word? "Oh, I know this," you might say. "I know that it starts with a B."

It's a sensation that we are all familiar with, and it turns out that this common state actually has a name. It is known as lethologica or the tip of the tongue phenomenon. Psychologists define this phenomenon as a feeling that accompanies the temporary inability to retrieve information from memory.

Why does it happen? The exact processes are not entirely clear, but it is more likely to happen when we are tired, or when the information is not well encoded or there is inferring memories present. It may serve as an alarm that there is something going on with the retrieval.

What is interesting is that:

The longer participants spend in that tip-of-the-tongue state, the more likely they were to have the same experience the next time they encountered that word. "The extra time that people spend trying to dredge up the word is what the researchers describe as "incorrect practice" time. Instead of learning the correct word, people are learning the mistake itself," suggests Humphreys.

The article advises:

Instead of struggling to bring forth the memory, simply looking up the answer might actually be a more beneficial way of resolving your next tip-of-the-tongue experience.

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