Why You Forget English Words: The Forgetting Curve and What to Do

Updated 5 July 2026 · Dmitrii Alekseev, founder of Vocabulex

Sound familiar? You look a word up, feel like you've got it — and a day later it's gone. That's not laziness or a "bad memory." It's how the brain works. Let's look at why words fade and what actually helps.

The Ebbinghaus forgetting curve

In the late 19th century, the German psychologist Hermann Ebbinghaus ran a series of experiments on his own memory and described the forgetting curve. The conclusion was blunt: if you learn something new and never return to it, most of it is gone within hours and days. After a day only part remains; after a week, almost nothing.

One key detail: forgetting is fastest right after learning, then slows down. That's why the first review is so valuable — it catches the word before it has fully faded.

Why the brain deletes words

This isn't a bug; it's a defense mechanism. Your brain takes in a huge flow of information every day and can't store all of it. So it keeps what proves its importance — what shows up again and again — and drops what didn't reappear. Meeting a word once tells the brain "random, safe to forget."

The takeaway: for a word to stay, it has to "prove" it's needed through repeated encounters. Not one cramming session, but several returns spread out over time.

What gets in the way of remembering

• Cramming in one sitting. Learn 30 words in an evening and you'll lose almost all of them by the weekend. The forgetting curve is working against you.
• Passive re-reading. Staring at a "word — translation" list is easy, but memory barely strengthens: there's no effort to recall.
• Words without context. A bare translation sticks worse than a word in a living example that shows how it's used.
• Rare, unneeded words. Anything you don't meet in real life has nothing to anchor to — those words drop out first.

How to beat forgetting

The good news: the forgetting curve can be outsmarted. Each review at the right moment flattens it — the word fades more and more slowly, until it stays for good. Three methods work together:

1. Spaced repetition. Return to a word on a schedule with growing gaps. It's the direct answer to the forgetting curve — details in spaced repetition for English vocabulary.
2. Active recall. Don't re-read the answer — try to recall it yourself first. The effort to recall is the moment of learning.
3. Context and examples. Learn a word in a sentence, ideally a new one each time, so it's tied to meaning rather than to one memorized card.

By Dmitrii Alekseev — founder of Vocabulex. He learned English after moving to the US and built the app he wished he'd had for making new words stick.