Babbel is a subscription-based language-learning app that includes 13 different languages to pick from. The compact 15-minute lessons are easy to consume for the learner on the go. To help you retain learned words in your chosen language, it uses the tried and tested "spaced repetition" method to sprinkle the set of words and phrases around through various vocabulary learning stages. Following the first lesson, available free of cost, Babbel's monthly subscription starts at $13.95, or there's an annual package for $6.95 per month.
Babbel is available for download on the App Store and Google Play.