SEVERAL ADS; DUOLINGO IS THE BEST WAY TO LEARN A LANGUAGE; ANNOYING AND DISTRACTING NOTIFICATIONS WHICH MAKES THE APP LOOK IMPATIENT; ANYONE WHO SAYS IT’S THE BEST WAY TO LEARN A LANGUAGE WORKS FOR IT; TWO PAID SUBSCRIPTION SERVICES; A HEART SYSTEM WITH ONLY FIVE HEARTS WHERE IF YOU LOSE THEM ALL THEY TAKE FOREVER TO REFILL CAUSING YOU TO POSSIBLY LOSE YOUR STREAK; STREAKS