I localized a part of my application with creating a base.lproj storyboard and 3 string files for it. It was a month ago and after that I added new view controller to app, b
There are two options:
Xcode can "reload" the file by converting the file to either an [Interface Builder Cocoa Touch Storyboard] file type or a [Localizable Strings] file type.
Use ibtool to extract the strings in your storyboard.
Open the Terminal application
Locate your Base.lproj directory
Use this line to extract the strings:
ibtool MainStoryboard.storyboard --generate-strings-file file_name.strings
After ibtool extracts the strings to file_name.strings, you can copy and paste it to your original .strings file
Visit for more info: https://conyac.cc/business/columns/localization_guide_ios