Duolingo

Few apps are as good at getting you to come back every day. Duolingo's gamified streaks, leagues and XP turn practice into a genuine habit, and the ad-supported free tier is generous, covering more than 40 languages including less-common options like Welsh, Navajo, Irish and even the constructed High Valyrian and Klingon (free-tier terms can change, so check before relying on them). The paid Super tier removes adverts and unlocks unlimited hearts, while the pricier Max tier layers in AI features such as roleplay conversations and Explain My Answer, which breaks down your mistakes. It sits below Babbel because its method is lighter on grammar explanation and free-form speaking: Duolingo is strong on recognition and vocabulary, so it suits anyone who wants consistency for free, but many learners use it alongside a more structured tool rather than on its own.