“When starting the app or game, the language of the operating system is used as default language e.g.: de_DE on a german device. If this exact language is not available, any file with the same language but different country is used. If no translation file of the system language is available, Felgo Engine will use English (en_EN) instead. Therefore, you should always provide an English version of your app or game. Ifen_EN.qm is also not available the texts will be displayed as you have stated them in your qml file.
The operating system language that is used when the app is started the first time is stored and will be overwritten only when the according GameWindowApplicationWindow::settings value is changed. It also won’t change when the system language changes. If you want the application to start always with the currently active operating system language you can use the property translation.useSystemLanguage = true.”