LSubs is a video player for learning a foreign language. It helps you to improve your vocabulary and grammar by watching movies or TV series. 

The way it works is that you are watching your favorite movie on a language that you prefer to learn with subtitles on that language. If you don't know some words or full sentences then just tap on this word or select the full sentence and you'll see the translation on your known language.

You need to do is to open the movie on LSubs, add the subtitles and then watch it. 

This video player supports all popular video formats, including MKV, MP4, AVI, MOV, OGG, FLAC, TS, M2TS, Wv, AAC.