Auto-change language according to system settings

FULL STEPS:

1. In the system settings of the device, select any language other than English.
2. Download app.
3. Open app.

WHAT YOU EXPECTED:
The language of the application corresponds to the language of the system. And when I change the language in the system settings, the application automatically also changes the language.

WHAT ACTUALLY HAPPENS:
The application language is always English by default. And when I change the language in the system settings, the application language does not change.