I can't imagine additional languages being added until we have some kind of executable file support. Having one real language in addition to ubasic makes some sense. Having more would just be a waste. Maintaining two is already a pain.
Porting random C code to CHDK is not trivial. Even lua, which is small and religious about being strictly ANSI had to be hacked up a lot. As zeno points out, memory is also very tight.
When loadable binaries are eventually implemented, people can build whatever scripting languages they want. Until then, use lua. It's not hard to learn.
