To allow for these differences among specific geographical, political, or cultural regions, locales are specified by two-letter, uppercase codes. The two letter country code uses the ISO-3166 standard. Variant code Differences may also appear in language conventions used within the same country. Variations inside a language and country pair are handled by adding a third code, the variant code. The variant code is arbitrary and completely application-specific.
Variants can have any number of underscored key words.
Esperanto Default Locales Default locales are available to all the objects in a program. If you set a new default locale for one section of code, it can affect the entire program. Application programs should not set the default locale as a way to request an international object. The default locale is set to be the system locale on that platform. For example, when you set the default locale, the change affects the default behavior of the Collator and NumberFormat instances.