Change Your Chromebook's Language by Follow these Steps..
Steps:
1. First, Turn On Your Chromebook..
2. After Chromebook Started "Sign in" into your Chromebook with Google Account(Username & Password)
3. On Chromebook Click in your Google Account or, Account Picture that located in the lower-right Corner on your Screen..
4. Click on "Settings" & again Click on "Show Advanced Settings" tab..
5. In The Language Section Click on "Customize languages and input" tab..
6. Now Select your Language that your want to make Your Chromebook's Primary Language..
(Click "Add" button for Adding Language that are not listed on your chromebook provided language list)
7. After Adding or Selecting Language, Click on "Display Chrome OS in this language"..
8. Now, You have to "Sign Out" to Complete This Process. for this Click on "Sign Out" Button..
9. Again "Sign In" into Your Chromebook using your Google Account Information(Username & Password)..
10. After "Sign In" the language you select will be displayed on Your Chromebook..
Its Done....