OS X supports a number of different languages, and either during installation or in the system preferences you can choose your default language in which to have the system display localized elements such as menu text and dialogue text. In addition to interface elements, Apple supports localization on some system files and folders, including the default folders in the home directory. This means that if you switch your system's language, the names Desktop, Movies, Pictures, Documents, and so on that are in your home directory should also be shown in the new language.
While this works for most people, you may run into situations where certain directories on the filesystem do not translate. Recently ADC member "Ryan" ran into a similar situation:
I'm running a MBP with Snow Leopard (10.6.7) in Simplified Chinese. In this setup the few special folders located in user's home directory (i.e. Desktop, Library, Documents, etc.) all have their special display names in Finder. However now even other folders are displayed as their Chinese names correctly, the Desktop folder is now displayed in English, in all places like Finder, side bars and file picker dialogs from applications.
In order for a folder in OS X to be translated, the system must first have a list of available translations for it, and then it must be flagged as a localizable option. The system has a list of translations for all of the default home folder directories in addition to a number of system folders, but if the folder is not flagged as being localizable then it will not translate and will display in English, no matter what language you choose.
The fix for this problem is to tag the folder as a localizable resource. While OS X uses finder flags and other metadata to tag various folders, another method (especially for folders and disks) is to use hidden files within them. This is how Time Machine disks are identified and associated with a particular system, and is how language localization for system and home directories works. In each localized directory there is a hidden directory entry (an empty file that takes up no space on the hard drive) for a file named ".localized" that is used to flag the directory for translation.
The file should always be in the home directory folders, but it may be missing if you have migrated your system, restored a faulty installation, or otherwise manipulated your home directory folders. Luckily, restoring the hidden directory entry is an easy task, and just requires the following steps:
Open the Terminal application (in the /Applications/Utilities/ folder).
Type "touch" followed by a single space.
Drag the folder that will not translate to the Terminal window.
Step three will have added a space to the command, so press the delete key once and then type "/.localized" to complete the command. When it is done the command should look like the following:
Press Enter to execute the command.
After the command has run, the folder should now translate to the system's default language. If it still does not, then try rebooting the system or running a general maintenance routine to clear the system's caches (specifically user and application caches).