I’m currently using the latest OSMC release (2016.04-1) on a RPii3. I have a bunch of MKV files with a French subtitles track. French has many “special characters”, like accents on the letters ‘a’ , ‘e’ and ‘u’ (à é è ù) or cedilla on letter ‘c’ (ç).
When watching these videos with subtitles, only regular characters are displayed: the accented characters aren’t displayed at all, not even replaced by a space or a square.
For example: “Il a reçu Hélène cet été” is printed as “Il a reu Hlne cet t”
This happens with both Arial and Teletext fonts. I’ve also tried some other fonts from the internet (copied to /usr/share/kodi/media/Fonts/) and the issue still occurs.