You forget new vocabulary so fast because unused memories fade on a predictable curve. A word you met once in a list feels solid that evening and weak a few days later if you never produce it again. That is normal memory, not a personal failure.
Cramming packs words in for a near-term quiz. Spacing and clearer cues fight the fade. Neither one is a fluency promise.
Why does the fade feel so steep?
After a first pass, the brain keeps less of what it will not need again soon. Recognition ("that English gloss looks familiar") fades slower than recall ("say the word from a real cue"). Lists and translation-only fronts train the easy job, so the hard job fails when you need the word in a sentence.
For the full drop-off story, see Why You Forget 80% of New Words. This FAQ stays short; the live post carries the longer curve walkthrough.
What actually helps keep words longer?
Two boring levers work together:
- Encoding: give the card a cue you cannot fake. Many learners put a picture on the front so they must produce the word, not nod at English. See Why I put a picture on the front of vocab cards.
- Timing: meet the word again before it is gone. Adaptive schedules such as FSRS pick the next due date from your ratings. Plain English: What FSRS means for vocabulary.
Honest ratings beat a green calendar. A quiet day of due reviews can keep more words than a loud day of new content you will not meet again in time. That is retention, not streak theater. For the habit-vs-retention scoreboard, see Is a streak the same as remembering vocabulary?.
What are the limits?
Forgetting will not stop completely. Bad cards, skipped due piles, and recognition-only drills still leak. Pictures and schedulers will not teach conversation alone. Use clearer cues to encode; use on-time reviews to slow the fade.
If you want that loop in product terms, open How Vidi Works when you are ready.