All country names are translated to the language the customer has chosen. Otherwise, you won't be able to offer your web site in all available languages. To display the country names in the language used in that country, you can copy these two files into your custom Aimeos extension:
The files must be stored in the ./client/i18n/country/ directory of your extension. If your default language isn't English, rename them to the language code of your default language (e.g. "de.po" and "de").