well done

Since your level is certainly at advanced English speaker level, so I would give you some feedbacks for you.

firm: it didn't sound right to me.

visited: the [ed} ending is stressed too hard, and the last vowel sounded like [ei] as in take.

Australian: look up online disctionary on how lian would be pronounced.

abroad: you might look up the online pronounciation dictionary for the second syllable.

if you go for General American Accent, you might check how you pronounce [t], Darwin, town.

It is very hard to give sugestions to advanced speakers, since we ourselves are also working on our own pronounciation problem.

Keep it going.