Take a look in your /Applications/Microsoft Office X/Shared Applications/Proofing Tools folder and see if anything untoward has happened to the files there. Use Finder/Get info to take a look at Ownership and Permissions, making sure you can access both the proofing Tool folder and the various dictionaries within.
Try looking in your HOME folder's ~/Library/Preferences/Microsoft. Quit all Office apps and remove the files Proofing Tools Preferences, Microsoft Component Preferences, and Microsoft Office Settings(10). Then try Word or Entourage again.
If that fails, re-insert the Office v.X installation CD, run the Installer, select Custom Install, uncheck everything except Office Tools/Spelling Checker.
If all else fails, you can run Remove Office from the Value Pack folder on the installation CD, re-install, and re-apply the 10.1.2 and 10.1.4 updaters.