All other languages are either not compiled languages with static typechecking or have too few eligible users. C# would also be an option if it wasn't Windows-only.
>>3
Scala is easy enough to learn if you have experience in Java. Also you can use all your Java codebase in Scala projects.
Haskell is MUCH harder (so hard that i quit when trying to learn it, by lack of real motivation i guess, or maybe was all that time working on Burger King)