KYW is one component of a language-learning system: a dictionary with a repetition schedule that holds on to the vocabulary you have already covered. Here is how it is built, what it deliberately does not do, and how it differs from Anki, Quizlet and Duolingo.
What KYW is
KYW is a dictionary with a system of repetitions on top of it.
It is not a course and not a universal card builder, but one component of a language-learning system – the component responsible for holding on to vocabulary already covered. The other components give you new language: they explain, teach, supply context, develop grammar, listening, reading and speech. KYW works with the result of that work – the vocabulary you have already met and must not lose.
This is why KYW fits almost any model of study. The words can come from lessons, a tutor, a university, private reading, series, podcasts, work or your own notes. The problem is the same in every case: a word can be learned – and quietly lost a month later.
Vocabulary growth is not only addition. If fifteen old words are forgotten alongside twenty new ones, the real progress is far smaller than it looks. KYW is there precisely to make the growth of a dictionary cumulative rather than circular.
How this component works
- The card. The definition is on the screen, and you type the word on the keyboard. That tests the ability to recall a word, not to recognise it among ready-made options. The answer is analysed letter by letter, so a typo is not counted as ignorance.
- The order within a session. First come the words that already need a repetition, then the new ones, then the weak spots – the words that keep failing. That order stops new material from being accumulated at the cost of the old: first hold on to what has been learned, then add to it.
- The schedule. The long intervals are calculated by FSRS-6; the order and the dynamics inside the session itself by our own engine. More in the Algorithm section.
- The dictionary. An account holds as many dictionaries as you need, named by you: “German”, “Latin”, “7A English”, “anatomy terms”. Words, tags, schedule and statistics are separate in each. Packs exist too, but their role is a supporting one: to hand vocabulary over and to organise it. You can build a pack yourself and give it out by a link, or take a ready-made one from the shared library. A word added from a pack becomes part of your dictionary as a whole and no longer depends on the author of the pack.
- Bulk edits. The whole dictionary exports into a single file and loads back in the same format, so large-scale work – unifying definitions, adding examples, renaming tags – can be handed to an AI. Before the changes are applied, KYW shows exactly what will change. Which words are in the dictionary is still your decision.
- Statistics. The main figure here is not how many words were once added, but how much of what you learned is still in memory.
The main difference
The difference is not in the number of features. Most learning services count, naturally enough, what you have added, passed and unlocked. KYW is built around the other side of the process – around what you stand to lose.
Learned words do not stay in memory by themselves. So the work here is arranged around a simple idea: before you go on growing your vocabulary, make sure the vocabulary you already have is still with you.
| Anki | Quizlet | Duolingo | KYW | |
|---|---|---|---|---|
| Unit of work | any card type you design yourself | a set of cards | a lesson in a course | a word and its definition |
| Where the words live | in decks you assemble | in separate sets | inside the course | in one dictionary of a language |
| Where words come from | you add them or take someone’s deck | ready-made sets or your own | the course picks them | your own study: lessons, books, series, work |
| Who decides what to learn | you | you | the course | you |
| Format of the answer | you define it yourself | several modes to choose from | the exercises of the course | definition on the screen, word from the keyboard |
| What happens after a mistake | the card comes back sooner | the set is run through again | lives and a repeated lesson | the word goes to the weak spots, worked on separately and shown more often |
| The main figure | cards due today | how much of a set is done | lessons, streak, league | how much of the learned vocabulary is still in memory |
| Game mechanics | none | game-like modes | the core of it | none |
The table compares how these services are built, not how good they are. Each of them has its own job, and in that job each is stronger than KYW: for universal flashcards go to Anki, for a course from scratch go to Duolingo.
KYW and Anki
Anki is a general-purpose flashcard system. It suits any subject, any card type and any scenario, but it asks you to design that system yourself: the card type, what goes on each side, how the decks are arranged, the repetition settings.
In KYW all those decisions have been made in advance: a word and its definition, the definition on the screen, the word from the keyboard. It is not a matter of the algorithm – Anki also calculates intervals with FSRS. It is that there is nothing left to design.
The main difference, though, is one of purpose. Anki helps you learn and repeat anything. KYW is first of all about not forgetting words that were learned somewhere else: it does not choose what you should learn, and it counts on vocabulary that arrives from lessons, books, series, work or another process of study.
KYW is deliberately narrower than Anki. It does not work offline and it is no good for medicine, road signs or geography – for all of that you need Anki. KYW makes sense where you need a dictionary of a language that brings covered words back on its own.
KYW and Quizlet
Quizlet is built around ready-made sets and various modes of testing. Words there usually live scattered across separate sets rather than joined into one dictionary, so the overall picture of accumulated vocabulary stays fragmented.
In KYW the main unit is your own dictionary, and a pack only delivers words into it. Packs do not disappear because of that – they help you organise your dictionary: you can build them, hand them out by a link and take other people’s, and a pack can carry not only a list of words but the text they occurred in.
Hence the difference in scenario. Quizlet sets are most often taken to learn material quickly before a lesson or an exam. KYW is there so that the same vocabulary is still with you six months later.
KYW and Duolingo
Duolingo is a course: it decides what to learn and in what order, and takes a learner from zero.
KYW is not a course, sets no syllabus and does not decide which words you need. It accepts the vocabulary already received from another process of study and helps you keep it.
So there is no need to choose between them: you can work through a course and keep a dictionary in KYW at the same time. The words from finished lessons are exactly the ones that go first once the course has moved on.
What KYW does not do
- It does not teach a language from scratch – it is not a course and not a syllabus.
- It does not replace a teacher – nor a textbook, reading, listening or speaking practice.
- It does not decide what you should learn – the list of words is yours, and so is the order of topics.
- It is not a universal flashcard builder – the format is fixed in advance.
- It does not invent a dictionary for you – an AI helps with processing and formatting, not with choosing the words.
- It does not rely on gamification – there is one measure here: how much of the learned vocabulary is still in place.
- It does not work offline – a session talks to the server.
Price and data
Free, with no ads and no selling of data. Deleting the account removes the words, the answers, the statistics and the packs at once.
Who it is for, and who it is not for
The core audience is people who have been studying a language for a while, keep studying it, and notice that they lose vocabulary faster than they accumulate it.
The second scenario is a teacher: a finished unit is collected into a pack and handed to the class by a link, after which the app returns that vocabulary to each student on its own, without a revision lesson set aside for it. The third is a company: the terminology of a product, an industry, its processes and its onboarding is collected into packs and given to the people who need it.
KYW is not for you if what you need is a course; if you have to study offline; if you want the app to decide what to learn; or if what keeps you going is competitive mechanics – there are none here.
Where to begin is in the How to start section.