Why can’t European Australians speak another language other than English but the Asian and Aboriginal Australians can?

My experience to Duke Skibbington’s is so utterly different, I’m all… “are you sure you’re Greek?” But of course, he’s 3rd generation, and I’m 1.5th generation. (2nd generation, but spent childhood in Greece.)

It is of course to do with assimilation, which is to do with the timespan your family has been in Australia, and with intermarriage out of the ethnic group.

• Aboriginal Australians who were part of the Stolen Generations underwent forced assimilation; they don’t know any of their indigenous language, to their distress. Aboriginal Australians still living a traditional lifestyle in the country’s north are likelier to have held on to their language.
• There have been Asians in Australia since the Gold Rush; those Asian Australians are unlikely to have retained their language across 6 generations. The Asian Australians I went to high school with and am still in contact with are 2nd generation; they don’t look like passing their language on.
• Second generation Greeks were known in the 90s to be outliers in how much stronger their retention of Greek was than for other ethnic groups (even though their Greek, as I experienced, was not so much conversational as a secrecy language). But now that we’re in the 3rd generation, their Greek is gone, as Duke reports (and I know other such Greek-Australians).

To the extent that the major wave of Asian migration into Australia was in the 70s–90s, and the major wave of (non-British) European migration into Australia was in the 50s–70s, European–Australians are on aggregate one generation ahead in assimilation. That’s the most one can say.