Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
Community Questions for Confluence - Keep questions and answers in one place with an engaging, community-driven Q&A discussion forum, powered by Confluence
Memrise - Learn a new language with games, humorous chatbots and over 30,000 native speaker videos.
Question2Answer - A Q&A site helps an online community to share knowledge.
Busuu - Join the global language learning community, take language courses to practice reading, writing, listening and speaking and learn a new language. Learn English with busuu's .
Stack Overflow for Teams - Everything you love about Stack Overflow in a private space.