Spaced repetition (SRS) is the principle of reviewing information at increasing time intervals: you see a new word today, then tomorrow, then in 3 days, then in 10 days, then in a month. Each time you successfully recall it, the next review is pushed further into the future. When you fail to recall it, the interval resets.
The Spanish Example
You learn “hablar” (to speak) on Monday. SRS schedules it for Tuesday. You remember it — next review is Friday. You remember it again — next review is in 2 weeks. Then a month. Then 3 months. After a year you’ve reviewed it 7-8 times and it’s in long-term memory.
Without SRS, you might drill the same 50 words every day — wasting reviews on words you already know — while words you half-know slip through the cracks.
Why It Matters for Your Spanish Learning App Choice
Every major Spanish learning app claims to use SRS, but the implementation varies enormously:
- Anki: The gold standard. Fully configurable. Shows you exactly when each card is due. Free on desktop/Android, $25 one-time on iOS.
- Duolingo: Uses a proprietary SRS-like system. Less transparent; you can’t see your retention curves. Works, but you’re trusting the algorithm.
- Pimsleur: Uses “graduated interval recall” — a specific, rigorous SRS implementation that’s core to the method, not a feature bolted on.
- Babbel: Has a review section with spaced intervals. Functional but not configurable.
If you care about efficient vocabulary acquisition, Anki or Pimsleur’s implementation are more rigorous than Duolingo’s.
Related Terms
- Graduated Interval Recall (Pimsleur’s specific implementation)
- Leitner System (the original physical-card SRS)
- Cloze Deletion (fill-in-the-blank format common in SRS flashcards)