How do I change the language of the Linux subsystem in Windows 10 (WSL)?

The Windows Subsystem for Linux (WSL) installation should automatically set the Ubuntu locale to match the locale of your Windows install. You can change the Ubuntu locale manually using the shell.

1. Run this command in bash.exe to change the language to US English:

   sudo update-locale LANG=en_US.UTF8
   

   If you get a sudo: unable to resolve host error whenever you run sudo,

   • Verify that you have a hostname set (with the hostname command).

     • If it isn't set, add it to the /etc/hostname file.
     • Ensure that /etc/hostname contains only the hostname.

     Edit the file with sudoedit /etc/hostname (assuming you can get that to work); see this.

   • Ensure that your /etc/hosts file contains entries for your actual hostname (spelled exactly the same) and/or localhost.  Again, use sudoedit.

   See Error message when I run sudo: unable to resolve host for more information.

2. Relaunch the bash.exe for the changes to take effect.

3. If that doesn't fix it, try restarting the service:

   sc stop  lxssmanager
   sc start lxssmanager
   

If you want to learn more about the bash in WSL, you can read the FAQ by Microsoft.

This manual describes different ways. Since in this case we are using Ubuntu, choose corresponding options. Summary:

• Change locale for current session only: LANG=en_US.UTF-8
• Change locale permanently for current user: add LANG=en_US.UTF-8 to ~/.bashrc
• Change default system locale: use LANG=en_US.UTF-8 in
  /etc/default/locale

According to locale -a the following English locales are available in my system by default: C, C.UTF-8, en_US.utf8.