Based on their social media accounts they still speak their language but speak English like any other Aussie. I speak French and Italian, more French since my whole dadās side is French whereas my mum is half-English and half-Italian. However, the French I speak is virtually just New Caledonian French (which includes a bunch of Australianisms) not the French that MĆ©tros like my family speak.
What seems to cause language loss is intermarriage and families not adequately teaching their kids their language and thus it wanes over time. Italian Americans are an older group than Italian Australians so language loss was even worse over there. Asian/Pacific Islander languages are thriving while European ones are struggling due to the greater cultural emphasis on language in Asia and the Pacific.
Italian is indeed by far the fastest declining language in Australia, dropping by a whopping ā43,556 from the 2016 to 2021 censuses. Greek does better but is still declining too, same goes for Croatian and Maltese. Serbian is interestingly thriving though and actually increasing. I think European families are starting to recover it a bit but as a second language. Since the Australian census unfortunately only asks about oneās language spoken at home (usually oneās first language), we donāt actually know how many people have learnt other languages.