My Lumia 1020's on-screen keyboard changed automatically from English to Chinese. How can I change it back?
You can go to Settings>> Keyboard and the select the preferred languages.
Further you can interchange between languages as shown in the picture.
Go to settings -> keyboard From there you can add and remove desired languages. If you have more than one language selected you can switch on the fly with the second button from left, bottom row, on the keyboard.