Lernu also has two correspondence crosues Ana Pana and Jen nia IJK . It is interesting that it's not obvious that they offer real language helpers for them though. The site started with only correspondence crosues and then they realized they didn't want to overburden their language helpers and created more completely automated crosues. I originally translated lernu into English while visiting the creators of the site in Belgrade (Serbia) for a week, so it's been interesting to see how it's evolved since 2002!