Vim and gVim in Windows doesn't recognize Mongolian letters Өө and Үү

Question

I'm trying to open and edit files with Mongolian text, written in Mongolian Cyrillic. In the cmd terminal and in powershell terminal if I choose Consolas font, everything is ok with Mongolian Cyrillic, letters Өө and Үү are displayed correctly. If I open any Mongolian files in terminal Vim or gVim window, it shows them as ? sign. I have such an option:

:set guifont?
  guifont=Consolas:h9:cRUSSIAN

I added to _vimrc:

set encoding=utf8
set termencoding=utf8
set guifont=Consolas:h11:cRUSSIAN          "to get proper font for Cyrillic
set fileencodings=utf8,cp1251,cp866,koi8r
"to get English menu instead of broken Russian
set langmenu=en_US                        
let $LANG = 'en_US'
source $VIMRUNTIME/delmenu.vim
source $VIMRUNTIME/menu.vim

This code lets me see files properly. But I still can't type either search this letters straight in Vim. While typing, gVim turns them to ?-s.

Please, give me some advise, what should I do to fix that problem?

Answer 1

Actually, the decision was to update gVim to 8.0 version, released just a few weeks ago. Then such settings were useful as well:

set encoding=utf8
set termencoding=utf8
set guifont=Consolas:h11:cRUSSIAN          "to get proper font for Cyrillic
set fileencodings=utf8,cp1251,cp866,koi8r
"to get English menu instead of broken Russian
set langmenu=en_US                        
let $LANG = 'en_US'
source $VIMRUNTIME/delmenu.vim
source $VIMRUNTIME/menu.vim