This build we're introducing a prototype translation engine. The goal is to have Construct 2 translatable in to different languages, but it is currently a work-in-progress and many parts of the editor (especially dialogs and alerts) are not yet translatable. However you can have a play with the automatically generated translation (leetspeak :)) and see if there are any issues. Beware of new typos and language-specific bugs, and anywhere you see [missing] or [???] indicates a problem so please report any sightings! Note translation is a technically complex feature so this may introduce new bugs even in to the English language editor.
Please note we don't currently recommend anyone start translating Construct 2 in to other languages, because it will be difficult to track the changes we make to the language files as we allow more of the editor to be translated. There may also be undiscovered bugs in non-English languages. It would be best to wait until the translation system is completely finished, then it shouldn't be much work to keep translations up to date from then on.
Plugin developers: fear not, the plugin SDK is unchanged. The translations engine has been deliberately designed so plugins and behaviors are written entirely in English, then translators can separately translate them. Construct 2 handles the translation in the UI so the engine internals remain in English and therefore fully backward compatible.
Please note there was some trouble with r81 and the bug that prevented exports working properly. r81 was a beta release which means it's for testing only and likely to introduce problems. If you want to avoid new problems be sure to stick to stable releases: set the update checking in Preferences to "check for updates" (not the beta option) and only install updates Construct 2 prompts you about. On the other hand, we appreciate beta releases getting tested too, but please be aware of the choice you make! The r81 bug was easy to work around but it still seemed to throw a lot of people. We'll also try to make the difference between stable and beta releases clearer on the site in future. Note r82 is also a beta release!