The default language of the keyboard can be changed at any time to have the desired language and layout available immediately when opening a messaging app or input field.

To arrange the keyboard languages on the OnePlus smartphone or to select the default language, simply select the edit mode of the added keyboards and drag a desired language to the first position.

Android 10 | OxygenOS 10.0
Step 1:  Open the  Settings
Step 2:  Tap on  System
Step 3:  Tap on  Languages & input
Step 4:  Tap on  Virtual keyboard
Step 5:  Tap on  Gboard
Step 6:  Tap on  Languages
Step 7:  Tap on  Edit
Step 8:  Tap and hold a  keyboard language
Step 9:  Drag the  keyboard language  to the first position
Step 10:  Release the  keyboard language  to position it
Step 11:  Tap on  Back
  1. Open the Settings
  2. Tap on System
  3. Tap on Languages & input
  4. Tap on Virtual keyboard
  5. Tap on Gboard
  6. Tap on Languages
  7. Tap on Edit
  8. Tap and hold a keyboard language
  9. Drag the keyboard language to the first position
  10. Release the keyboard language to position it
  11. Tap on Back

OnePlus Instructions