The whole method, in plain words — just the how, the evidence behind it, and what to pair it with.
Before you ever open Flua, we build the path for your language: which words to learn, in which order, inside which sentences. Every sentence is checked, word by word, against everything the path has taught before it — so each card contains only words you already know, plus exactly the one new word or pattern it's teaching. You can't hit a wall of new words, because the wall was removed before you arrived.
One unknown word in a sentence you otherwise understand is a puzzle you can solve. Two is a guessing game. Zero is a lullaby.
The order isn't alphabetical or thematic — it's frequency-first: your first 1,000 word families are the ones that appear in roughly 80% of everyday spoken language in corpus studies. Counting exact forms, the forms taught in the French, Spanish, and German decks make up 71%, 72%, and 78% of all words spoken on screen, in that order. Researchers call the underlying idea comprehensible input — you acquire a language from material you can almost, but not quite, fully understand. Flua's job is keeping you at that edge on every single card.
One goal at a time is what keeps the path fast: you learn to understand the language before you polish producing it. Splitting your effort between the two slows both down — pronunciation, grammar and reading come far easier when they ride along on sentences you already understand, instead of being taught as separate chores.
The audio serves that goal: every card plays its sentence at full, natural speed — real rhythm, real emotion, no slowed-down classroom voice. You hear the line, guess the one new word, then check — so what you practice on is speech the way people actually say it. Comprehension leads, but not alone: the iPhone and Android apps add speaking cards that turn sentences around once you know every word in them, and everything you hear you also see written.
Flua tracks how well you know every word and brings each one back on your memory's schedule — quick while it's new, then right before you'd forget. The gaps grow as your memory does — minutes, then days, then weeks. That's the century-old finding behind spaced repetition (Ebbinghaus's forgetting curve), and it's why a short session every day compounds where an hour of cramming evaporates. There are no game-style lessons to repeat and no levels to grind — just the next card your memory actually needs.
Your Flua Index estimates the share of everyday sentences made entirely of words within your vocabulary. Your study time, recall history and the share of everyday speech you understand are tracked from the first session and shown to you plainly — and the study totals behind them are published, aggregated and anonymized, on the transparency page.
What to pair it with. Flua is built to be your main daily study for the first stage of a language: understanding everyday speech, and in the iPhone and Android apps saying sentences you already know. A conversation at another person's speed takes practice with people, so add a tutor or conversation partner. What's published is beginner material: 1,008 to 1,058 cards per language, teaching 551 to 959 distinct words, 5 of 7 at Flua's A1 target of 700 or more; if you already follow everyday speech, around B1, it's below your level. Paid access to a language includes every card we've published for it plus every future level we publish.
The founder's own run — more than 1,000 Japanese words and most basic grammar in about 20 tracked hours, using a shared Japanese Anki deck built on the same one-new-thing rule, before Flua existed — is one person's result, not an official test. Your own pace appears on your own screen from session one.
The method is the pitch. The quickest way to judge it is the first few cards.
Try the first cards free →No account needed. Your first 150 cards are free, and what you learn free stays reviewable free.