Busuu is a language learning application and website that provides games, exercises and other resources to help users learn languages like Spanish, French, English and more. It teaches vocabulary through flashcard exercises and incorporates words into dialogues and writing exercises. Users can chat with native speakers, record their voice, and receive corrections on writing from the Busuu community. The application guides users through beginner to intermediate levels of lessons for 12 languages, providing 3 free courses per level with additional premium content. Exercises include matching vocabulary to images or sentences, filling in blanks, pronunciation tests and more. The document provides a detailed overview of the Busuu app and its effectiveness for language learning.