Is en_UK an illegal locale?

Question

So far I had always used \'en_UK\' for British English. Today I got an error when using it with Zend Framework because the locale is not included in the long list of recognized

Answer 1

You cannot simply invent locales! They are already defined. So "en-gb" is British English, whereas "en-us" is American English. If you use "en-uk", you are just making up a code.

As to why the official code is "en-gb" and not "en-uk", I think basically because there is no such thing as United Kingdom English. The language variant is British. Note that the difference between Great Britain and the United Kingdom is:

UK = GB + Northern Ireland

So by naming the variant "en-UK" it's as if you are saying that you want to include the way they speak in Northern Ireland within this category. But why would you want to do that? From a linguistic perspective it makes no sense, as Northern Ireland English is closer to Irish English (en-IE) than British English.