Spaced Repetition for Thai: When Reviews Finally Stop
TL;DR: A Thai letter you keep getting right comes back seven times and then never again. The first three correct answers are spaced 1, 3 and 7 days apart and master it; the four after that land at 21 days and then grow by a factor of 2.2, so the letter reappears roughly 32, 78 and 180 days after you first met it. When the next gap would pass six months the item retires and leaves the queue for good. One wrong answer at any point resets the whole thing to zero and puts the letter back in front of you tomorrow.
The first three answers, and the one that undoes them
Phayan is an app for learning to read Thai script, and it schedules every letter and word you meet on a fixed ladder rather than a difficulty estimate. Get an item right and the next review is 1 day away. Right again, 3 days. Right a third time and it is mastered, with the last of the short reviews 7 days out.
Three in a row is the whole mastery test, and the counter is consecutive. A wrong answer on the fourth day does not knock you back one rung: the count goes to zero, the mastered flag comes off, and the item is due again tomorrow. That is deliberately harsh, and it is the same shape Anki uses, because a letter you got wrong is not 80 percent learned. It is a letter you got wrong.
Which letters go into the ladder in the first place is a separate question, and the answer is that Phayan introduces them a few at a time in consonant-class order rather than alphabet order, because the class is what later decides the tone.
What happens after a letter is mastered
Mastery is not the end of the reviews, it is the point where they get long. The first review after mastery lands at 21 days, and every review after that multiplies the previous gap by 2.2. Here is the whole life of a letter you never get wrong, counted in days from the first time you saw it:
| Correct answer | Gap to the next review | Day it lands on |
|---|---|---|
| 1st | 1 day | Day 1 |
| 2nd | 3 days | Day 4 |
| 3rd, mastered | 7 days | Day 11 |
| 4th | 21 days | Day 32 |
| 5th | 46 days | Day 78 |
| 6th | 102 days | Day 180 |
| 7th | Would be 224 days | Retired instead |
Seven correct answers spread over about six months, and the item is finished. The average gap across the mastered part of that ladder is roughly 46 days, which is the number the curriculum was designed around: long enough that recalling the letter is real work, short enough that most people still can.
Why the queue is designed to empty
When the next gap would come out over 180 days, Phayan retires the item instead of scheduling it. Retired means never due again, not due in two years. This is the part most spaced-repetition tools do not do, and the reason to do it is the maintenance tail: a system that keeps everything alive forever hands a learner who finished the course a review queue that never reaches zero, which is how people quit an app they had already succeeded at.
The trade is honest and worth stating. An item you have recalled correctly at 21, 46 and 102 day gaps is about as durable as a review schedule can make it, but it is not guaranteed for life, and Phayan is choosing a finishable queue over a permanent one. If a retired letter does slip, you meet it again the next time it appears inside a word.
The one place you grade yourself
At the end of a round you can rate it Hard, About right or Easy, and that sets the next review at 1, 3 or 7 days. It is worth being precise about what this does and does not touch, because self-grading is the thing that goes wrong in flashcard apps.
- It never grades the answer. Whether you got an item right is decided by what you typed or tapped, not by what you thought of it afterwards. The rating cannot mark a wrong answer right.
- It moves one review, once. The rating overrides the next due date and nothing else. It does not touch the correct-count ladder, so rating everything Easy does not master anything faster.
- It is spent by the next answer. Once you answer the item again, scheduling goes back to the ladder. There is no way for a rating to compound.
So the honest summary is that Phayan takes the correctness judgement away from you and hands back a small, bounded say over pacing. That is a narrower thing than the Anki self-grade, which is the point: the comparison of decks, charts and apps goes through why the correctness judgement is the one you do not want to be making about yourself.
What to actually do with this
Mostly nothing, which is the argument for a fixed ladder. But three things follow from the numbers that are worth knowing:
- The first eleven days are the expensive ones. Three reviews inside a week and a half is where the work is. Skip them and you are not slowing the schedule down, you are restarting it, because the letters you miss come back at zero.
- A quiet review day is not a wasted one. After the first month most days have only a handful of items due, and clearing them takes a couple of minutes. The queue is small on purpose.
- Do not fear the reset. Getting a letter wrong in month four costs you three short reviews, not four months. The ladder is cheap to reclimb; avoiding the item is what is expensive.
All of this runs whether or not you have made an account. Progress is kept locally first, so the ladder starts on the first letter you meet rather than after a sign-up screen, and every item carries audio. If you want the tones themselves rather than the scheduling behind them, the tone rules table is the page for that.
Frequently asked questions
What is the best review schedule for learning the Thai alphabet?
A short ladder followed by long gaps: something close to 1, 3 and 7 days to get a letter in, then reviews measured in weeks and months to keep it. Phayan uses exactly that and stops scheduling an item once the next gap would pass six months. Anki will do the same job with a shared Thai deck and gives you far more control, at the cost of grading yourself on every card.
How do I stop reviewing a letter I already know?
You do not have to do anything; it stops on its own. After seven correct answers spread over roughly 180 days, Phayan retires the item and it never comes back into the queue. There is no button for retiring something early, and that is intentional, because feeling like you know a letter is exactly the judgement the ladder exists to check.
Is it safe to take a week off in the middle of learning?
Your progress is safe and nothing is deleted, but items that fell due while you were away are still waiting and the ones you have half-learned will likely come back wrong. Phayan keeps everything without requiring an account, so a break costs you review accuracy rather than data. Expect a heavier first session back and a few letters knocked to the bottom of the ladder.
What is the difference between mastered and retired in Phayan?
Mastered means three consecutive correct answers, after which the gaps stretch from 21 days upward; retired means the item has run out the whole ladder and will never be scheduled again. Mastered items still appear in reviews, roughly three more times. Retired ones do not appear at all unless you meet the letter inside a new word.
If I rate everything Easy, do I finish faster?
No, and the schedule is built so you cannot. The Hard, About right and Easy rating sets only the next review date, to 1, 3 or 7 days, and the next answer clears it. Mastery still takes three consecutive correct answers and retirement still takes the full ladder, so the rating changes when you see an item and never how far along it is.