Internationalization of Flutter
We can find some detailed knowledge about internationalization in the developer document, Internationalizing Flutter apps.
Extra step for iOS
For iOS we have an extra step. We need to follow the last Appendix: Updating the iOS app bundle.
We have an ios folder in the Flutter project. In that folider we have a file iOS/Runner/info.plist.
Open it wtih Xcode and edit it like this.
There are several candidates for the supported languages. The list is far limited to that of Android’s.
It seems that we cannot diferectiate Chinese Traditional in Taiwan and in Hong Kong.