BUSUU

busuu is a social learning app for languages. It is available on web and via iOS and Android. Courses are available in twelve languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Russian, Polish, Turkish, Arabic, Japanese and Chinese. Learners select one or more of these languages and work through the self-paced lessons, studying vocabulary and grammar, which they can then practice in spoken or written conversations with native speakers in the busuu community.

Busuu was designed to incorporate the communicative elements of social networking into self-study language learning. Through its website and mobile apps, the business offers free and premium paid-for access to courses in 12 languages.

busuu offers courses based on (CEFR) levels A1, A2, B1 and B2. The study material for each language is broken down into thematic lessons, each based around common conversational scenarios. Lessons contain vocabulary and grammar practice, pronunciation exercises, interactive quizzes and conversational practice with native speaker members of the busuu community. Learners act as both student and tutor, correcting one another's work. They can converse via asynchronous voice recording or text chat.

There are two classes of member: ordinary member, and paying premium member. Grammar content, spoken and written conversations and some features, such as offline mode and spaced repetition vocabulary training, are available only to premium members.^[5]

Uniquely, the platform encourages collaborative learning by offering users the unique opportunity to learn the language and practise their listening, writing, reading and speaking with assistance from a rapidly growing community of native speakers. In this way, every busuu user is both student of a foreign language and tutor of their own ‘mother tongue’.

Here are ss' of application

Here is a link of video which  givesiinformation about a grammar subject.