TL;DR
Understanding a language (Recognition) and speaking it (Production) use different parts of the brain. Most apps only test Recognition. To speak fluently, you must practice Production specifically by testing yourself Source -> Target (English -> Japanese) without hints.
"I understand everything they say, but I can't speak!" This is the most common complaint among intermediate language learners. It's not just you—it's biology.
Recognition (listening/reading) and Production (speaking/writing) use different neural pathways. Recognition is effectively a matching game: you perceive a sound and match it to a concept. Production is a creation game: you have a concept and must synthesize the sound from scratch.
The Gap
Most apps (Duolingo, Anki default decks) focus heavily on recognition. They show you a foreign word and ask for the English meaning. This builds a massive passive vocabulary but leaves your active vocabulary atrophied. You become an "expert listener" who is mute.
Bridging the Gap with Full-Sentence Flashcards
To fix this, you need to practice Production explicitly. But relying on single words is dangerous—you might learn the word for "run" but not know which preposition to use with it. This is why Full-Sentence Mining is superior to single-word lists.
Babelbits treats every card as two-sided skills. We track your "Source → Target" (Production) score separately from your "Target → Source" (Recognition) score. If you can read the card but can't say it, we only punish the production score, keeping your recognition progress intact. This honesty allows you to pinpoint exactly where your "speaking block" lies.