Spell check adds a letter to end of word!

When I am adding or editing a comment to a PDF file in Acrobat 10 and I misspell a word, I click on the word and choose from a list of spelling suggestions. When I choose the correct spelling Adobe Acrobat adds an extra letter to the end of the work.

          For example: tofay -> todayy or lanuage -> languagee

However, when I run a total document spell check the suggestions, when selected, do not add an extra letter.

I have uninstalled and reinstalled both Adobe Reader XI and Acrobat 10 yet the problem still persists.

Suggestions?