I know some people use YouTube for language learning, but I think it's still a bit under the radar for many. I mean, where else can you find millions of hours of video content with decent quality (mostly) and in virtually every language in existence, about basically any topic there is?
The app has two main goals: 1. Allow interacting with the transcript to copy and translate, which you can't do with the YouTube app. 2. Facilitate interaction with the video content through exercises, to improve understanding and retention.
I'm using it currently to polish up my Mandarin, which I learned to a decent level some 10 years ago. For this kind of casual use case I find it quite good, if I do say so myself.
There's currently around 1k users across Android and iOS. Korean seems to be popular as a target language, as well as Turkish, which interestingly is being learned in Somalia of all places. But according to my stats, it turns out that the most popular language pair is English->English. So right now I'm working on improving the experience for this kind of "monolingual" learning.
The app can be used for free, with an optional ad to unlock exercises per video.
iOS: https://apps.apple.com/us/app/lingolingo-language-challenge/...
Android: https://play.google.com/store/apps/details?id=com.lingolingo...