I'm sure there are as I've seen job postings with asking for scala experience. Since I can't think of any off the top of my head here's some similar-ish languages.
http://www.scala-lang.org/documentation/ It looks very cool....and has a lot of desirable attributes like parallelism. I wonder if someone could write an entire trading platform using it ? Given the complexity of such an app, that would be a great test of it's abilities.
Java 8 has included lambda expressions, partly due to Scala success. It might be a good idea to take a look at that. Parallelism is also incorporated.
Not sure what was used to create Scala. It's a functional language whereas Java is OO before Java 8. Both Java and Scala compile to the same bytecode used by JVM. So it's possible to use libraries interchangeably. Scala is a different language all together. It's more like Haskell and Lisp. But as I said, you can build Scala libraries that Java apps can use.
Definitely you can write a trading application with it just like you can with Java. But the inherent issues with a Java trading applications will also be a problem with Scala since they both use the same JVM ie garbage collection and JIT warmups.