Just take a look how it handles Hebrew font and do the same.

I already did it, but how can I can add my code to the SCUMMVM release on SourceForge?

Thanks for your reply.

just submit your font to our patchtracker.
Eugene

And what should I do for this? I already have a Russian font.
My solution is to add several lines of code into defs.h & display.cpp to define a new font array.

I want to translate this game to Russian.
So far I found at least one issue: the font is hard-coded in the resources.
What will be the best way to add a support for Russian font?

I was able to recompile SCUMMVM with my custom Russian fonts, but I suppose it will break other languages.