To Set the Language Environment Variable on Windows 7, Windows 8.1, and Windows 10
1. On the desktop, right-click Computer and select Properties.
2. Click Advanced system settings.
3. In the System Properties dialog box, in the Advanced tab, click Environment Variables.
4. To specify a new variable, under System variables, click New.
5. In the Variable name box type LANG or PRO_LANG.
6. In the Variable value box, type the language variable appropriate for your language.
7. Click OK three times to exit the System Properties dialog box.