It's a fun game and I think it could help people increase their typing speed in foreign languages. I want to be faster at typing in some other languages like Japanese, Russian, Ukrainian, etc.
Okay as per checking the words are hardcoded and the way I check how the player type each character is using their ASCII code. I think it will take time to verify if I change this to other languages. This will need research on how characters work in other languages like typing A + B will result to C rather than typing C in english will be always C.
I'm happy that you're interested. I think instead of using ASCII codes, you need to use unicode values to see what characters are being typed. Here's a site that maps them out nicely: https://codepoints.net/
In particular, this page: https://codepoints.net/basic_multilingual_plane
Russian uses cyrillic characters, so they are here: https://codepoints.net/cyrillic