A feidn of mine was born and brought up in the US, married a German, and has lived since her marriage (nigh on 40 years now I think) in Oz. Her 3 sons therefore have American, German and Ozzie nationalities. Although they are all living in the US they plan one day to come back to Oz (she says), all 3 travel on Oz passports, and haven't lost their Ozzie accents.

Cheers
JennieG