Recognition evidence, not a mastery score. New words can be challenging and enjoyable. Parent test answers are excluded; adult use of ordinary study cannot be distinguished.

Initially missed tracks cards first encountered in this period. Subsequent success is an observation, not proof of lasting mastery. Daily numbers are saved answers, not minutes studied.

Off by default. Turning on starts with your next study session. Turning off stops collection immediately. Parent test is excluded. No names, microphone recordings or third-party analytics.

Last seven Shanghai calendar days, from enabled browsers only. Active time means the app was visible and unpaused, including loading; it does not measure attention. Narration completion means playback reached the end, not comprehension. Restarts count as new playback starts. Missing events and abrupt exits can leave sessions incomplete. Raw events expire after 30 days; daily totals after one year.