The free Adobe Reader 9 Spelling Dictionary Pack lets you perform spell checks on such things as form fields and comments (Abobe Reader is the free software that lets you open, view and print PDF files). You can also add and edit custom words to your user dictionaries for future reference. In other words, as you are filling out forms in Acrobat Reader, you can now check the spelling in 32 languages. To use the dictionaries within Acrobat Reader, go to the top menu and choose Edit-Preferences-Spelling and select the dictionary you want to use.
Acrobat 8 (full version - English)
DOWNLOAD Adobe Acrobat Reader 9 Spelling Dictionary Pack