You can set your language preference in your profile and we have the encoding on the site now set so that both English and Cyrillic will display correctly no matter if you set English or Russian in your profile.
The problem with the buttons is they are set globally for the whole forum. I expect an expert php programmer might be able to write or amend the code to allow separate selection but that is beyond my capability as I work mostly with html and only basic php.
I guess it will have to be a compromise for all of us but I am sure given time, we will all become used to the features of the forum no matter what language they are in
Oh and adding your alternative nick in English or Russian is possible but it would have to be done under the "ranks" setting and this would be a long and tedious process, having to be done separately for each individual user. The best way would be to add your nick to your signature, which you can do in your profile page.