Problem while entering the system

In the language configuration (gnome-language-selector) you can choose your account and the primary system language.
You should set the later to "English (UK)" (or whatever county you like).
Also in the keyboard settings (gnome-keyboard-properties) change the layout to US and press the button to apply the settings systemwide. You can set them back to Russian later.

Well, thanks for the answer but how can I change my keyboard layout to US.
I can change only the default system language with the help of bottom-left menu of the login screen.
Ctrl+Shift or Alt+Shift is not working.

- run "LC_ALL=C gnome-keyboard-properties"
- go to the tab "Layouts"
- click "Add..."
- choose "United States" / "USA"
- click "Add"
- remove all other entries from the list (but remember them)
- click "Apply System-Wide"
- close the window
- restart the system
- you should have US layout only now, on log-on and when logged-in
- you can restore your preferred layout now (in the same dialog as above)
- BUT: do not click "Apply System-Wide" this time

After following this steps you should have a login with US layout and a session with an other.

Sorry for the stupid question,
how may utilize during login to enter LC_ALL=C...?

Sorry for the stupid question,
how may utilize shell during login to enter LC_ALL=C...?

Well, I used Ctrl+Alt+F1 to enter console during login. Then I see black screen and something like root@... but if I try to enter anything I get only strange symbols instead of English letters.
So I don't know how to enter LC_ALL etc
Thanks for the attention to the problem.

There's an other way to fix that problem:
- at boot time just after the BIOS hit Esc to enter the boot menu
- choose the first recovery option
- wait until a menu appears
- choose the option "root"
- enter "nano /etc/default/console-setup"
- change "XKBLAYOUT" to "us"
- save and exit (with Ctrl+X, Y)
- at the prompt hit Ctrl+D
- back in the menu choose the option to resume normal boot

Your gdm login should use the US keyboard layout now.

Dear Mr. Kruger,
unfortunately even in recovery mode when I try to enter anything in shell I see only diamonds or russian letters. That's why it's not evident how to enter any command you propose.
Thanks for your attention

In this case it get harder:
You will have to boot from the Live (Installation) CD in English.
You need to mount your root partition. It should be visible in the Places menu. If there are many hard disk you should use the one that matches the size of your root partition and contains directories like bin, dev, etc, lib, home...
Now right click on one of the directories inside, choose Properties to find out it's location. This could be for example "/media/disk".
Open a terminal and enter "sudo su". Enter "nano /media/disk/etc/default/console-setup" (adapt it if the location was different from /media/disk)
Now follow the steps 6 to 8 from my previous message and reboot.

Well, thanks a lot. It worked. Although I failed for some reason to change the console-setup file using shell.
I just opened it with sudo gedit and modified the string XKBLAYOUT.
Have a good day!