Duolingo ABC is a delightful literacy app that brings Duolingo's gamification expertise to early childhood reading education. The fact that it is completely free with no ads, no in-app purchases, and no subscriptions is remarkable -- this is a genuine public good from Duolingo. The curriculum progresses logically from letter recognition through phonics to reading short stories, aligned with Common Core standards. Interactive stories and letter tracing exercises are engaging for the target 3-8 age range, and the adaptive pacing prevents frustration. The parent dashboard for tracking progress is a thoughtful inclusion. Offline support means it works during car rides and flights. The main limitation is scope -- it focuses exclusively on English reading, and once a child has mastered the content, there is no advanced path. The Android rating (4.3) lags behind iOS (4.7), suggesting some platform inconsistency. For what it sets out to do, though, Duolingo ABC is exceptional.