In theory, Dalvik executes any virtual machine byte code, created for example with the compilers of
Are there already working versions of bytecode compilers for Dalvik available for other languages than Java?
Scala works very well.
I'm programming my Android application projects in Scala (Website written in Chinese with some screenshot, source code @ GitHub), and it is pretty easy to setup the evnviroment (without IDE, using SBT as build tool).
It could access every API in Android SDK, so anything you could do in Java, you could do it in Scala too.
You may check this blog entry to see how to build Android application with Scala and SBT.
I haven't played with it but I know that Scala works.
The dynamically typed languages wont be possible until Dalvik supports JIT (Just In Time) compiling. I believe there is JIT support in one of the experimental Eclair branches, but it is not yet officially available/supported in Android.
