Phrasal verbs are a system, not a list: the particle workshop
Instead of drilling 'kick off' and 'roll back' as isolated flashcards, the new workshop groups phrasal verbs by particle and teaches each particle's core spatial image first — so unseen phrasal verbs become guessable. Plus 72 real dev collocations, and the Practice tab finally shows all its tools.
A frustrated-but-precise piece of user feedback set this batch: "kick off나 roll back 이런 전치사를 전치사 개별모음으로 묶고… 실제 실무 콜로케이션 제대로." Two asks hiding in there: treat phrasal-verb particles as a system, and add the verb+noun pairings engineers actually say.
The particle insight
Phrasal verbs are the single biggest "sounds native vs. sounds translated" gap for ESL engineers — and the standard way to learn them (flashcards per verb) throws away their structure. The particle carries a spatial image: off is "something attached detaching — triggering or cutting away" (kick off, sign off, back off, kill off); out is "from inside to outside, expanded or exhausted" (factor out, fan out, max out, stub out); up is "into existence/completeness" (spin up, stand up, free up, queue up). Learn the image once and unseen combinations become guessable.
So the workshop has eleven particle groups. Each group carries a coreKo — the particle's image explained in two Korean sentences — and opening a particle drills its whole family: 58 newly-authored gap-filling verbs merged with the 44 phrasal cards that already existed (matched by token, so "spin up" lands in up and "back out" in out). The trick that makes it pedagogy instead of taxonomy: the coreKo rides in every card's glossary slot, so every rep re-imprints the system, not just the item.
Collocations and the tab fix
The collocation bank is 72 verb+noun pairings from real engineering speech — merge a branch, drain the queue, rotate the credentials, page the on-call — each with the full annotation set (Korean nuance explanation, example translation, an eliciting question that doesn't give the answer away, and a concept glossary line where needed).
Both banks went through the standing dual-lens verification (native-speaker naturalness, then Korean/technical accuracy). Ten corrections, two of which would have actively taught wrong mental models: "dial down the log level" inverts direction (lowering the level increases output — fixed to "로그 양"), and a "tire rotation" metaphor for credential rotation (tire rotation swaps positions; it doesn't replace anything — exactly the wrong picture for key replacement).
And one plain UX bug from the same feedback: the Practice tab had been rendering a single tool (the pattern drill) while five others hid behind home-screen cards. It's now the menu it should have been — six tools plus the new workshop, every section visible.