You can upload your own Playlist by using mylist.
While streaming a movie or a series, you can change the language with the RED button;
It will show you a menu where you can find Audio Language. In this section, you can switch between the languages.
While watching a movie, you can use the RED key for adding subtitles or removing.
RED - Choose audio track when streaming/watching a video (webOS Toggle DVB input (Netcast TVs), and it opens the settings menu for movies where you can select the audio track and subtitles.
GREEN - Electronic Programme Guide (EPG) select video play mode