Is "English" or "en" the preferred .lproj folder name now?

Question

In Apple's documentation and example code, I see lproj folders both named with the name of the language, such as "English", and with an ISO 639 code, such as "en".

What is the definitive naming requirement? I have not been able to find it.

If there isn't one, what are the advantages and disadvantages of each type of name?

Answer 1

See also: Using “en” instead of “English” for your Xcode project’s development region, which tells you how to hack your Xcode project so that using en is less of a pain.

Answer 2

Now of course after some more Googling I do find the definitive guide:

http://developer.apple.com/iphone/library/documentation/MacOSX/Conceptual/BPInternational/Articles/LanguageDesignations.html#//apple_ref/doc/uid/20002144

"English" is old. Don't use it. These are still recognized, however. Also I note that Xcode still shows these when you create a new localization. Filed as rdar://problem/7219844

"en" or "eng" is current. Do use it.

Answer 3

The ISO 639 code is the preferred name.