For languages that roughly share the same alphabet as English, it seems more like learning a few new words, rather than actually learning English.
If you take a look at the actual project you'll see that translating the language features to another language (and alphabet!) is cool, but not actually enough once you want to start interacting with libraries.
Which essentially means that without learning english, you will be stuck in a technical ghetto with the only way out being to learn english, or reimplement the world.
I still think this is highly interesting as a teaching tool; showing kids what is possible without requiring them to learn english may be a good motivator to actually learning english, but this doesn't seem to have many applications beyond as an introductory teaching tool.