1. Make sure that you have date+time set correctly in your phone settings. Also, you may need to charge your phone to complete next steps.
2. Select Settings > keyboard and tap add keyboards to display the list of keyboard input languages that can be installed.
3. Select your preferred keyboard input language you want to install, to do that tap the checkbox near the language name. Tap done to start downloading.
4. Wait for your phone to finish downloading, then you are notified that An update is ready to install.
5. Tap install and your phone will automatically restart.
6. Wait for your phone to install the update, a new screen stating that the update is ALMOST DONE. Once ready, tap done.
7. The next time you use your keyboard, you will see a button on the bottom row of keys that indicates which language you are currently using on your keyboard. Tap the button to switch between all the languages you have selected. For example, if you usually use a US English keyboard, tap the ENG button, and the keyboard switches to the next language. You can also tap and hold the button to reveal all the languages you have added and then switch to the one you want.
To remove keyboard:
Select Settings > keyboard. Press and hold the input language you no longer need and select remove.