We collect only what we need to run the service: your phone number (to sign you in), your grade and language choices, and your learning activity such as lessons watched and daily-quiz results.
Your phone number is used to send one-time sign-in codes through your mobile operator. We never sell your personal information to anyone.
On the leaderboard, other students only ever see a masked name (your first name and last initial) — never your full name or phone number.
You can sign out at any time from your profile. If you have questions about your data, contact your operator's support line.