Mariada Subtitle files are added automatically according to what's available at the time the title is added to the site, so some films may have Greek subs available, while others may not. But if there is a movie or show that doesn't have subs in the language you're looking for, you can always go to sites like opensutbitles.org, download the relevant subtitle file and upload it directly to the LM player - just make sure it is in .srt format.