An issue that I see occasionally on new Macs is that they’re set to use a language different than mine when I take them out of the box. In my case, the alternate language is most often set to French (for unknown reasons), rather than being set to US English like I’m expecting.
OS X normally handles this issue as part of the installation process, by asking which language is preferred and using that for the OS.
However, when I set up new machines, I’m past the point of selecting the language that way. Fortunately, there are alternate ways to change the language used at the login screen. For more details, see below the jump.
If there is just one user account on the Mac, you may be able to change the language globally using the Language & Region preference pane in System Preferences:
1. Log into the Mac
2. Open System Preferences
3. Select Language & Region or its equivalent in the Mac’s current language.
Note: The relevant icon displays the United Nations flag
4. Set the Region you want
5. After the Region information is set, click on the plus ( + ) button.
6. Select the language you want to use.
7. When it asks if you want to use the new language as the principal language, select the button that says to use the new language.
8. The new language should now appear marked as the principal language.
9. If desired, select the old language and click the minus ( – ) button to delete it.
10. When you close the preference pane, you’ll be prompted to restart to set the new primary language.
11. After the Mac restarts, the login screen should now use the language you set.
The Language & Region preference pane should also now show the new language and Region settings in the desired language.
If there is more than one user, or if you just want to change the login window’s language, there’s an alternate tool to use:
1. Log into the Mac
2. Open Terminal
3. Run the following command with root privileges:
languagesetup
4. A list of languages will be displayed.
5. Type the number that appears next to the language you want to use. Once entered, press Return on your keyboard.
6. Exit out of Terminal
7. Restart your Mac
8. After the Mac restarts, the login screen should now use the language you set.
For more information about this, please see the Apple KBase article linked below:
https://support.apple.com/HT202036
