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

Duolingo
Learn Spanish, French and more
You earn crystals as you complete lessons. You can buy more from the Shop tab
More interactions from‏‏‎ ‎
Duolingo
Add friends to compete with. You can search by name or find them from facebook
Profile and settings
During login, it asks for your age, name, email and password
Duolingo Plus lets you download lessons offline and removes ad. You can start with a 7 day trial
Bottom sheet for wrong answer
Achievement leveled up modal
You can tap the country flag on top to add more languages and switch between them
It quizzes you with audio and visual questions to make you understand and to increase recall