So you have completed your iOS or Mac app and wonder how your interface would react to different localized string sizes, here is quick tip that would save you time.
In Xcode 5
You can double the length of your strings to test your interface by adding and setting to YES the following launch argument to your Xcode scheme: NSDoubleLocalizedStrings
When you run your application each string will be double and it will look something like this:
In Xcode 6
In the new Xcode 6 this feature is called Double Length Pseudolanguage and comes preconfigured in the launch options of your scheme and can be selected directly from the Application Languages drop down menu as illustrated in the following screenshot.
A few other flags you may consider using for testing your internationalized app include:
Testing Right-to-Left Languages
To test right-to-left layouts, add launch arguments or set the equivalent user defaults. For iOS apps, enter this line in the Arguments pane of the scheme editor:
For Mac apps, enter both these launch arguments: