Day 22 of Japanese still feels like homework. You open Anki after work and 80 reviews are waiting. You skip a night, and it's 150. Then you stop opening it. Two months later it says 600, and the thought of it is heavier than the reviews would be.
This is for coming back after a break, when the motivation faded and you want the language back without starting from zero. The short version: much of it is still there, relearning goes faster than the first time, and the way back is small sessions on fixed days, starting where you stopped.
Is what you learned still there?
A study tested 733 people on Spanish they had learned at school, up to 50 years later. What they remembered fell for the first 3 to 6 years, then stayed about the same for up to 30 years. Large parts were still there after 50 years, though most had barely used Spanish since (Bahrick, 1984).
A two-month break is a much smaller gap than that. Our reading: much of what feels gone is hard to reach, not lost.
Why is relearning faster?
Memory researchers call it savings: the share of the first learning you don't need the second time. If a list took 25 repetitions to learn and 20 to relearn, you saved 20% (Murre and Dros, 2015).
It holds for languages. A study of 304 people who had learned Japanese or Korean while living abroad found the strongest savings effect yet reported in studies of relearning words. The advantage shrank the longer they had been away, and it went with how many words they still knew (Hansen, Umeda and McKinney, 2002).
How long until it feels automatic again?
The popular "21 days" is not what the research found. In a 12-week study, 96 volunteers each picked one simple daily habit, an eating, drinking or activity behaviour, and did it in the same context every day. Reaching 95% of the most automatic it got took between 18 and 254 days (Lally and others, 2010). The 66 days you see quoted is the median among the 39 people whose data fitted the model well.
Language study wasn't tested, and 20 minutes of reviews is more work than a glass of water. Our reading: give it months, and judge it by whether you keep coming back, not by how day 22 feels.
The same study found that missing one opportunity did not materially affect how the habit formed. A missed evening is not a restart.
What about the review pile?
With a backlog of overdue reviews, Anki's manual recommends that you stop introducing new cards until you catch up, since new ones can make the backlog worse. For a large backlog it suggests the "Relative overdueness" review order. And Maximum reviews/day caps how many reviews Anki shows in a day, even when more are waiting (Anki manual).
A day that shows 30 reviews is one you can finish. A day that shows 600 is one you close.
An example: an Anki and Genki backlog
This is a first plan Omodo made in a test on 9 Nov, for a made-up learner. It is not a user's result, and Omodo has not measured its own results yet.
The learner typed: "Get back into Japanese. I was using Anki and Genki but my reviews piled up and I stopped about 2 months ago. Weeknights after work, 20 to 30 minutes, at home." They had reached chapter 7 of Genki 1, Anki had about 600 reviews waiting, and they wanted to "read manga without looking up every word".
The first milestone: "Read five chapter 7 example sentences aloud with three lookups or fewer", by Friday 13 Nov. The sessions, as Omodo made them:
- Tuesday 10 Nov, 8pm, 15 minutes: Do ten Anki reviews. Check the review count. If Anki won't open, read the chapter 7 vocabulary list in Genki aloud instead. "Your reviews piled up, so ten is a small start."
- Wednesday, 20 minutes: Read three chapter 7 example sentences aloud. Read each one twice. Look up each word you don't know in the chapter's word list, then read that sentence again.
- Thursday, 20 minutes: Do twenty Anki reviews. "Twenty is twice Tuesday's ten, so more of the pile moves."
- Friday, 20 minutes, the first win: Read five chapter 7 example sentences aloud. Sentences 4 to 8, looking up no more than three words.
It doesn't try to clear 600 reviews in a week: it asks for 30. It doesn't go back to chapter 1: it starts at chapter 7, where they stopped. And the win is a small piece of what they want, reading with fewer lookups.
If you'd like a plan like this for your language, at times you're free, you can start one at omodo.ai.