Hi,
the ApplicationGetSystemLanguage gets the system language, and returns it as a string.
this way you know what the default language is on the pc/mac/android/... Device.
Then its up to you how you set the languages.
you can use for example arrays start with a list with your supported languages.
To know which languages you can include, look
herethen have an array for each language.
or you can use xml(using Datamaker)