Love the idea; can I kindly ask if you're expanding to include German?
Although it would be even better (for me) if one were able to import their Anki decks and have your app figure out the level of "competency" for each word. This is the biggest gripe I have with adopting a new language learning app: Having to re-learn vocabulary that I am already 100% confident in.
Also, I would love to be notified when the Spanish version comes around - is there any way for that?