The Games keep mentioning the real world countries, like AFRICAN Elephant, CHINA, AMERICA. Also note that the 'Regions' are exactly that, regions. Not countries, hence the bus like route systems with the 'Japanese' areas. Each 'region' is stated to be based on a real life region, ie Kanto=Kanto, Johto=Kansai, Hoenn=Kyuushu, Shinnoh/Sinnoh=Hokkaido, Isshu/Unova=New York/Jersey, Orre=Arizona. These places just have different names and are shaped differently in the Pokemon world for gameplay purposes, but the countries names are the same.
This is likely from Gen2 onwards, when 'Fantasy Counterpart' kicked in due to Pokemon becoming an international hit, as Kanto has the same name as the real Kanto region.