New words light up, everywhere you read.
Sluka is a reader for the open web. It highlights the words you haven't learned yet on any page, in a book, under a video or in a chat window, and remembers what you know from one site to the next. Nothing leaves your machine.
One payment. No subscription, no account, no server to depend on.
New Learning 1 2 3 4 Known — no highlight at all
This demo starts you off knowing the 700 most common words, with 200 more in progress; your grades stay in this browser. The article is fetched through sluka.app for the demo only — the extension reads pages in your own browser and sends nothing anywhere.
Where it works
Anywhere the words are.
The open web
Articles, forums, fiction, documentation. Any page in the language you are studying, including pages set vertically (直排).
Video
Captions on YouTube, Netflix and other players are highlighted, with an autopause that waits for you before the line disappears.
Chatbots
Conversations with an assistant in your target language are read as they stream in, which makes a chatbot a source of endless graded input.
Books
PDF, EPUB and plain text, with the same highlighting and the same word list. Scanned PDFs are the exception — there is no OCR, deliberately.
Your phone
An Android app with the same reader and shelf. Your words sync with your computer over your own network — not through anyone's server.
Twenty-one languages
One at a time, so the shelf and the statistics always belong to the language you are actually in.
- Bundled dictionary
- Chinese
- Cantonese
- Japanese
- Korean
- Italian
- Read and tracked
- English
- French
- German
- Spanish
- Portuguese
- Swedish
- Danish
- Norwegian
- Finnish
- Polish
- Russian
- Ukrainian
- Greek
- Turkish
- Vietnamese
- Indonesian
Chinese counts as one language in both scripts. Cantonese is its own language, with jyutping. Korean is cut into words inside each phrase.
Listening counts too
Your hours on YouTube and Spotify, counted without being asked.
Reading is half the input. Sluka also counts time spent listening to the language you are learning — and only that language. Time is credited against the track's own clock rather than the wall clock, so a paused tab, a stalled player or a sleeping laptop earns nothing, and a podcast at 1.5× credits the time you actually spent.
Desktop
YouTube and the Spotify web player, in any tab, with nothing to press. Spotify's desktop app is invisible to extensions, and always will be.
Android
Anything playing on the phone, the Spotify and YouTube apps included. Sluka reads what the player itself reports, from any app.
iPhone and iPad
Spotify and YouTube count inside Sluka's own browser, where both are built in. iOS lets no app see another app's playback.
The method
Massive input, in the tradition of Steve Kaufmann.
Sluka is not a neutral tool. It is built around one way of learning a language, and it is bad at every other way on purpose.
“Listening and reading are so powerful.” Steve Kaufmann — polyglot in some twenty languages, co-founder of LingQ, who began Russian at sixty
Kaufmann's argument is that a language is absorbed rather than studied. You take in a very large amount of real content you actually find interesting, you meet the same words again and again in contexts that differ slightly each time, and your brain extracts the patterns without being told the rules. Grammar arrives as a feeling for what sounds right, long before it arrives as a table. He names three things that decide whether it works: attitude, time spent with the language, and the ability to notice what the language is doing.
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Real content, not learner content
The web is the library. Read the articles, forums and fiction you would have read anyway — Sluka works on whatever is in front of you rather than on a walled catalogue of graded texts.
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Volume beats drilling
No flashcards, no spaced repetition, no review queue that grows while you sleep. A word is learned by meeting it in twenty sentences, not by being tested on it in isolation.
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Ambiguity is allowed
You do not have to understand every word to make progress, and Sluka never blocks the page until you do. Words you skip stay lit and come back around.
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Listening counts as much as reading
Time under video captions and time in an audio player are tracked alongside words read, because half of the input is the half you hear.
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Progress is a word count
The number that matters is how many words you know and how much you have got through. There is a daily streak for anyone it helps, and no badges, no confetti and nothing that goes red after a quiet week.
If you have used LingQ, the model will be familiar — that is deliberate, and Sluka can import your exported words. The differences are that this runs on the whole open web instead of inside a content library, that your data stays on your machine, and that you pay once.
Read the method in fullHow it works
Grade a word in one keystroke, then get on with reading.
There is no review session and no test. You read something you wanted to read anyway, and the words sort themselves out as you go.
Open any page
Sluka reads the HTML, so highlights stay glued to the words when you scroll, resize or zoom. No OCR, no screenshots, no copy and paste.
Hover, then press a key
Hovering shows the reading and the meaning. 1–4 sets how well you know it, K marks it known, X ignores names and numbers.
It follows you
A word learned in an article is already known in the next book, video and forum thread. Your vocabulary is one list, not one per site.
Counted honestly
Words read are credited only for text on screen long enough to be read. Scrolling to the bottom in two seconds credits two seconds.
Yours, on your machine
Words, books and statistics live in your own browser. No account, no server. Back it up to a file whenever you like.
Price
Fifteen dollars. Once.
There is no subscription and there never will be. Renting a reading tool forever is the thing this was built to get away from.
Free to try
The first 1,000 words are free.
Nothing is time-limited and no feature is switched off. The free version stops letting you save new words once you are tracking a thousand of them — everything already saved keeps working, and so does every language, every book and every page. You build a real vocabulary first and decide afterwards whether the tool earned fifteen dollars.
DownloadSluka is not in the Chrome Web Store, Google Play or the App Store yet. If you would like to know when it lands, write to [email protected].
Every feature, every language, every device you own.
- The browser extension and the phone app
- All twenty-one languages and every bundled dictionary
- Books, video captions, chat, sync and statistics
- A licence that verifies offline, forever, with nothing to phone home to
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No account. No renewal. No server that has to still exist next year.
Paid through Polar, who handle the card and the tax. Your licence appears on screen the moment the payment clears, and arrives by email as well.
Refunds
If it doesn't work, you get your money back.
The policy, in full
If Sluka has a technical fault and you can show it to me at [email protected], you get a full refund. That is the whole condition.
Showing it to me means enough to see the fault: the page or book you were reading, what you expected, what happened instead. A screenshot or a short screen recording is usually plenty. Include your licence key.
I would much rather fix the problem than take the refund, so expect a fix to try as well. The refund does not wait on it. Refunds are issued through Polar to the card you paid with.
Lost your key? Have it emailed again — it is derived from your purchase, so it can always be reissued.