You already can --
Lisp: Nu
Ruby: MacRuby/RubyMotion
Basic: Objective-Basic
Lua: LuaCocoa, LuaWax, TLC
JavaScript: JSCocoa
Perl: CamelBones
More: http://cocoadev.com/wiki/CocoaBridges
You already can --
Lisp: Nu
Ruby: MacRuby/RubyMotion
Basic: Objective-Basic