Hello there, please refer to the following steps, thank you.
1. How to add system language?
realme UI 7.0 & 6.0: Settings > System & updates > Language & region > Edit > Click the language you want to add.
realme UI 5.0 & 4.0: Settings > Additional Settings > Language & region > Edit > Click the language you want to add.
realme UI 3.0 & 2.0: Settings > System Settings/Additional Settings > Language > Add Language > Click the language you want to add.
realme UI R & Go & T & U & S Edition: Settings > System > Languages & input > Languages > Add Language > Click the language you want to add.
2. How to modify the system's default language?
realme UI 7.0 & 6.0: Settings > System & updates > Language & region > Long press the language you want > Drag it to the top of the list > Click to confirm the change
realme UI 5.0 & 4.0 & 3.0: Settings > System Settings/Additional Settings > Language > Long press the language you want > Drag it to the top of the list > Click to confirm the change
realme UI 1.0: Settings > Language & region > Language > Click the language you want to use > Click done
realme R & Go & S & T & U Edition: Settings > System > Languages & input > Languages > Long press the language you want > Drag it to the top of the list
3. How to delete an added language?
realme UI 7.0 & 6.0: Settings > System & updates > Language & region > Edit > Select the corresponding language > Click Delete
realme UI 5.0 & 4.0 & 3.0: Settings > System Settings/Additional Settings > Language > Click the upper right corner > Edit > Select the corresponding language > Click Delete
realme R & Go & S & T & U Edition: Settings > System > Languages & input > Languages > Click the upper right corner > Remove