Todays post is brought to you by the letter G

Interesting linguistic problem has intreegued me since i returned from HK to find that the chineese call the 'white man' gualo

why do several very distinct cultures call the whiteman names beginning with the letter G

Gringo - Hispanic
Gora - Indian
Gualo - Chineese
Gaijin - Japanese

anyone else have names for the whiteman beginning with G?