As your in tutorial, many other NSLocalizedString() examples provide the original english text as the first argument i.e
NSLocalizedString("Press this button", comment:"Explanation")
The problem with this is that it can quickly become a nightmare to maintain if a) the text is changing, b) the same text is used elsewhere but in a different context (so a slightly different meaning). I would recommend NOT to go this route but use the ‘key’ argument in NSLocalizedString() truly as a key that uniquely identifies the text. Something like:
NSLocalizedString(DIALOG_LBL_PRESS_BTN, comment:"Explanation")
Yes, i know it isnt as easy on the eyes but in the long run will save you a bunch of time.