As a resident Duolingo apologist this is certainly awesome! I appreciate how little landing-page fluff there was before I could give it a shot. I tried Japanese and felt it was only reasonable in tandem with my in-built translation extension, since Kanji-reading knowledge itself is a major hurdle of learning. Furigana would really help this, but personally, being able to translate the words I pick helps a lot during the challenge of hearing new vocabulary in native Japanese.

As well, I am learning multiple languages, and noticed that the settings panel seems to be the way to switch between them. I think it's a little unnatural to force a user to do this, but if there's an intention for bookmarking languages of interest for separate collections of videos & transcription exercises I can say I'd be happy to pay, honestly. The pricing itself seems reasonable and I appreciate that I can feel the app out for free.

Interesting project!