In some Linux distributions (in my case it is Arch) you can meet with such warning in terminal:
bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
#en_US.UTF-8 (even if you got another locales uncommented) in locale file and regenerate them.
In Arch distribution run command:
sudo nano /etc/locale.gen
Uncomment appropriate locales, save file and run: