Duolingo is a free service for learning foreign languages, which also acts as a crowd-sourcing translation platform. The developer Louis tried to find a way to translate thousands of pages on the Internet without resorting to questionable machine translation or expensive services of professional translators. The system he invented solves this task; real people translate web content while performing exercises on learning languages. Now online you can learn Spanish, French, German, Italian and Portuguese (for those who know English) and English (for Spanish-,Portuguese and Italiano — users).
When the user selects the language he wants to learn, the site determines his current language level, and then invites him to translate sentences of varying complexity — from elementary to the most complex. Even the absolute beginner can learn in a such system. The learning process takes place in the form of interactive games. A user accumulates bonuses and proceeds from level to level by performing the task correctly. Also grammar references, dictionaries of new words and other useful tools for learning are available.
The site also handles quite well with this second feature — translation of real web pages. Translations that require specific skills, is offered only to users who have reached the appropriate level. In addition, a system of evaluating the quality of translated excerpts though others, result in high accuracy translations. Customers pay for the service of translation, and those who learn the language, are able to use the site for free.