In case you are wondering, the system language is the language that show up in the menu bar and everywhere in the system. It is, however, not the same as the input language, which is the language you use for typing. If you are passing your laptop to your Dad/Mum/Granny who are not familiar with the English language, you might want to change the system language to one they are familiar with so they can navigate around easily.
Changing the system language
In Ubuntu, open the System Settings and launch the “Language Support” option.
You will see a list of languages in the “Language for menus and windows” section. This list contains all the languages already installed in your computer. If your preferred language is in the list, you can drag it to the top of the list. This will set it as the default language for menus and windows. Click the “Apply System-wide” button.
If your preferred language is not in the list, click the “Install/Remove Language” button. This will open up a window with the full list of languages. Scroll down the list to find the language you want and put a check beside it. Click “Apply Changes”.
After the installation, you should see your preferred language in the list. Drag it to the top of the list and click “Apply System-wide”. Restart the computer and you should see the new system language in action.
More Language Option
Using the above method will only change the menu and window’s language, but it will not change the input method. For example, if you have changed to Chinese (like I do above), when you type in the keyboard, English characters will still appear instead of Chinese. To change the input language, simply change the option for the “Keyboard Input” from “Default” to “IBus”. You should see a keyboard icon at the system tray. Click on the icon to switch the input language.
In addition, the numbers, dates and currency format will remain the same even though you have changed the system language. To change the number format to match the region you are at, go to the “Regional Formats” and select the format in the dropdown. Click “Apply System-wide” and restart the computer.
That’s it.