The question What options are there for doing spell-checking in emacs discuss various spell checking solutions for Emacs. Emacs ispell interface uses external tools such as Aspell or Hunspell for spell checking. Considering the fact that many free dictionary files are available (for example by Openoffice see for example the dictionary file en_US.zip) I am wondering if it would be possible to write a native spell checking function in Emacs using such free dictionary files.

Added: More precisely I am wondering if there are existing packages which can be used for spell-checking (without using external tools such as Aspell or Hunspell) within Emacs. A tool which checks if a word is correct and if not suggests some corrections.

In case the answer is negative, any hint to do this would be helpful.