When I lived in Australia I met about 5 girls named Tiahn. I have never heard it anywhere else and it doesn't appear on popularity stats so it always confused me. It was pronounced tee-AHN. One of them definitely spelled it Tiahn I never saw the other ones write their names down, I first guessed it was Tiarne but I guess I was wrong. Tiahn.
Also I heard
Hayley,
Brooke and
Chloe a lot. Oh and
Hamish. That one isn't really popular anywhere else.