I Kinda Like Languages - We have free interactive introductory courses in 30+ languages. No fees or registration.
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.
Esperanto in 12 days - The Fastest Esperanto Course for the Basics
Memrise - Learn a new language with games, humorous chatbots and over 30,000 native speaker videos.
Rosetta Stone - Rosetta Stone is the world's most popular software for learning languages. It is offered at a cost of just $169 when purchased outright, but it is also possible to purchase language programs in a subscription format that offers ongoing support.
Drops - Visual language learning.