You can learn more tips like this if you can make it to the Switching to Mac Workshop- Wednesday, March 14th at the Davis Family Library Rm 201 from 1:00-3:00.
Try this step-by-step instruction for those who want to change the system language in the Mac OS X.
Changing the system language in Mac OS X
Step 1. Click on “Apple Logo“, and then click on System Preferences
Step 2. In System Preferences; click on the International icon.
Step 3. At the right hand side of the window, look for a flag with “Languages & text” beneath
Step 4. Change the system language from English to Simplified Chinese (or any language you choose). Do this by dragging the Simplified Chinese on top of English.
To see the changes right away without logging out by clicking on the red button to close the International settings first:
Step 5. Click on the “Apple Logo”, and then click on Force Quit Finder:
Step 6. Select Finder and click on the Relaunch button:
Step 7. Click on the Relaunch button again:
Step 8. Now you should see the changes
I retrieved this from the link below which includes pictures!: