[KyleGoetz]

As someone who studied in Japan, I'd like to point out that using Japanese with your exchange student is terribly rude. The student is likely moving to Australia to learn English, not to teach Japanese. He's likely spending a huge sum of money to be there, too.

I always hated it when people would speak English with me in Japan, because I didn't go to Japan to speak English; I went to learn Japanese.

Of course, if the student is just using "learning English" as an excuse to chill in a gorgeous country for a while, then no worries, mate!