When localizing an application it is often tricky to know which name in the Languages list corresponds to the desired language. So I made a cheat sheet to help me lookup the right value.
Also, a pro-tip I have about doing localization work is to practice a few times finding the Language screen in the Settings app before you change the language. After you switch languages you need to be able to find it again without reading any labels.
The right column includes the english translation of the name and then the IETF BCP 47 Language Code. This two digit code is what is often used by NSLocale.
I also setup a permanent short URL for it at: http://david-smith.org/languages