If you are trying to check the localization of the application, then there are simpler ways than changing the language on the device.
You can run applications with a flag to indicate the country:
that is, for swedish you can use the flag -AppleLanguages (sv)
Of course, on a simulator or device, you cannot normally launch an application with a flag, unless you create and run it through Xcode, where you can set startup arguments for each circuit.
: https://abizern.org/2012/03/18/simple-localisation-testing.html
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