With KoboBulkFixer (Option - Install Liberation font), we can have your kobo support other languages.
what we need to do is:
1) Replace the 4 ttf files in the KoboBulkFixer with fft file support your language, but have to keep the file name unchanged, that's:
LiberationSerif-Bold.ttf, LiberationSerif-BoldItalic.ttf, LiberationSerif-Italic.ttf and LiberationSerif-Regular.ttf.
2) Run KoboBulkFixer with option "Install Liberation font" checked.
note: if it doesn't show your language after the fixing, you need to check the epub file (unzip it), make sure the 4 .ttf files are in the same folder as the .css file.
Attached is the Chinese version of the KoboBulkFixer. two Chinese font file can be selected: SofiaSans.ttf and DroidSansFallback.ttf.
your can replace those 4 fft files with any of these two, currently, DroidSansFallback.ttf is in this <
KoboBulkFixer_Chinese.zip>