Nostalrius Begins - Quality wow vanilla realm (1.12)

Hi there,

For some reason I cannot type cyrillic letters while trying to type something in russian on this server. When I used to play retail World of Warcraft I would just switch from latin letters to russian cyrillic letters by changing the language in the bottom right corner;

http://gyazo.com/c1eaf5dc8cb87d2f425ce1f52bfddc8c

But when I try to type something in-game on this server all I get is this result;

http://gyazo.com/2f2b10c23899ec7a0522ccbeafc08dce

Does anybody know what the problem could be? I used to play on other private servers before but I have never experienced this problem.

I have the same problem when I try to write in Ukrainian..