Learning Science

Spaced Repetition for Thai Vocabulary

Why we forget, when to review, and what makes Thai vocabulary different. The science behind effective flashcards—and why generic apps fall short.

The Forgetting Curve

In 1885, Hermann Ebbinghaus made a discovery that changed our understanding of memory: forgetting follows a predictable exponential curve.

100% 50% 0%
0 1 day 1 week 1 month
70%
Forgotten within 24 hours
90%
Forgotten within 1 week
95%
Forgotten within 1 month
The good news: Each time you successfully recall information at the right moment, the forgetting curve flattens. Spaced repetition exploits this by scheduling reviews just before you'd forget.

The Spacing Effect

Spreading reviews over time is dramatically more effective than cramming. This isn't intuition—it's one of the most replicated findings in cognitive psychology.

Massed Practice (Cramming)

All at once
  • Feels productive in the moment
  • Good for tomorrow's test
  • Poor long-term retention
  • Wastes time re-learning

Spaced Practice

Spread over time
  • Feels harder initially
  • Requires planning
  • 50-100% better retention
  • Builds lasting knowledge
The research is clear: A 2006 meta-analysis by Cepeda et al. found that spaced practice produces an effect size of g=1.01—a large, consistent benefit across hundreds of studies. This means the average student using spaced repetition outperforms 84% of students using massed practice.

Jam Kham's 3-Layer System

Most flashcard apps only use one layer of spacing. We use three—because Thai demands more.

1

Within-Session Micro-Spacing

New words appear 3 times per session in different formats, spaced by 2-5 other cards.

Based on Landauer & Bjork (1978): expanding retrieval practice builds stronger initial traces.
Result: Creates strong initial memory traces before you leave the session.
2

Long-Term SM-2 Scheduling

The proven SuperMemo algorithm schedules reviews across days and weeks—1 day, then 3, then 6, then adaptive.

SM-2 algorithm (Wozniak, 1994) optimizes review timing based on your performance.
Result: Reviews happen right before you'd forget, maximizing retention with minimum reviews.
3

Curriculum Sequencing

Smart ordering balances skill types (40% comprehension, 30% production, 20% listening, 10% tone) and interleaves lessons.

Rohrer & Taylor (2007): interleaving improves transfer and long-term retention.
Result: Prevents skill imbalances and keeps learning varied and engaging.

Why Thai Requires Specialized Features

Generic flashcard apps work fine for French or Spanish. Thai has challenges they don't address.

Tones Change Meaning

The word "mai" has 5+ different meanings depending on tone. Generic flashcards treat tones as optional.

Jam Kham tracks tone accuracy separately and includes dedicated tone cards.

No Word Boundaries

Thai script has no spaces between words. "ฉันกินข้าว" looks like one unit but is three words.

Our syllable breakdown shows exactly where words begin and end.

Classifiers Everywhere

Thai uses classifiers for counting—you can't just say "three dogs." It's "dog three classifier-for-animals."

Vocabulary cards include classifiers and teach them as part of the word.

Production vs. Recognition Gap

Reading Thai is easier than producing it. Most apps only test recognition.

8 card types include production cards that force recall from English to Thai.

The Research Behind Spaced Repetition

Our approach is grounded in over a century of memory research.

Ebbinghaus (1885)

Memory decays exponentially without review. 70% of new information is forgotten within 24 hours.

Memory: A Contribution to Experimental Psychology
Pimsleur (1967)

Introduced the concept of graduated interval recall—reviews spaced at increasing intervals.

A Memory Schedule
Cepeda et al. (2006)

Meta-analysis showing distributed practice (spacing) produces a large effect size (g=1.01) compared to massed practice.

Distributed Practice in Verbal Recall Tasks
Roediger & Karpicke (2006)

Testing effect: retrieval practice produces 50% better long-term retention than re-reading.

Test-Enhanced Learning
Dunlosky et al. (2013)

Ranked practice testing as the #1 most effective learning technique out of 10 studied.

Improving Students' Learning With Effective Learning Techniques

Frequently Asked Questions

How many new words should I learn per day?

Research suggests 10-15 new words per day is sustainable for most learners. The limiting factor isn't learning—it's the review queue that builds up. Too many new words creates an unmanageable backlog within weeks.

Why does spaced repetition feel harder than re-reading?

Desirable difficulty. Active recall is cognitively demanding—that's exactly why it works. The effort of retrieving information strengthens the memory trace. Re-reading feels easy but creates weak, recognition-only memories.

Should I review every day?

Consistency matters more than duration. 15 minutes daily beats 2 hours once a week. The algorithm is designed around regular sessions—skipping creates review pile-ups that undermine the spacing benefit.

What if I keep failing the same card?

That's normal and useful. Difficult cards get more frequent reviews until they stick. Jam Kham also identifies patterns—if you consistently fail tone-related cards, you might need dedicated tone practice before more vocabulary.

Start Building Vocabulary That Lasts

Experience the 3-layer system for yourself. Start free with 50 core Thai words.