You earn crystals as you complete lessons. You can buy more from the Shop tab

The curriculum is arranged linearly as a timeline with tests interspersed in between

Profile and settings

Duolingo Plus lets you download lessons offline and removes ad. You can start with a 7 day trial

There are posts by other learners and mini "games" that help you test your skills

It quizzes you with audio and visual questions to make you understand and to increase recall

During login, it asks for your age, name, email and password

You have 5 lives. When you run out you can wait, practice, or refill by spending crystals

Achievement leveled up modal

Redeeming a reward

Daily streak touchpoint on homepage

In app purchase

You have 5 lives. When you run out you can wait, practice, or refill by spending crystals