The emulator is in a very early stage.
Commercial games cannot be run right now because the hardware emulation is very incomplete, it still support only a little number of the CPU and GPU calls/opcodes, and the overall interface is yet very simple. Not to mention the emulation engine right now is an interpreter, which will be *very* slow for any commercial games. In time, whenever the core code is robust enough for that, I'm guessing the interpreter will eventually be replaced by a Dynamic Recompiler, probably a JIT recompiler or something like that. At least that's how emulators usually progress. (It was that way with N64, PS2, GC/Wii, etc)
Commercial games will be supported when the emulation is mature enough to run them, and that will take time to happen.
I'm not sure if I understood you correctly, but if you are asking about the GUI language it is in english, and personally I don't think it is worth to implement any kind of multilingual interface yet, the GUI is likely to change a lot as new features and settings are implemented.
I'll probably write a FAQ about this later today and post here.