If you have the paid version of NoteTab Pro or Std, you can download spell-checker dictionaries and a thesaurus without charge by visiting the web page below:
http://www.notetab.com/dictionaries
Please note that NoteTab Light and the trial versions of NoteTab do not include any spell-checker and thesaurus features. So downloading the dictionary and thesaurus files is of no use as they will not work in those versions of NoteTab.