To show subtitles with a video file, the name of the subtitle file must follow the naming convention where the subtitle file matches the video file. The language can also be specified:
Video file: (video file name).(video file extension)
Corresponding subtitle file: (video file name).(language specifier).(subtitle file extension) or (video file name).(subtitle file extension)
For example, if the video file is named "video.mp4" and you have English subtitles, the subtitle file can be named "video.en.srt" or "video.srt".
Languages that can be used and their corresponding language specifiers are:
German - 'de'
English - 'en'
Spanish - 'es'
French - 'fr'
Japanese - 'ja'
Korean - 'ko'
Russian - 'ru'
Chinese - 'zh'