Now to select a language, you need to click the flag in the top-right corner of the menu, then, a new menu will pop up. You can pick your language there.
Polish and Chinese are not shown by default! You need to enable 'Hidden languages' in the settings first. It's one of the few new settings in 0.2.4. Of course, they are very incomplete. Chinese has a lot of GUI done, though. But almost no events.