GNU Aspell spell-checker

 GNU Aspell is a spell-checker which can be used either as a standalone
 application or embedded in other programs. Its main feature is that it
 does a much better job of suggesting possible spellings than just about
 any other spell-checker available for the English language, including
 Ispell and Microsoft Word. It also has many other technical
 enhancements over Ispell such as using shared memory for dictionaries
 and intelligently handling personal dictionaries when more than one
 Aspell process is open at once.
 .
 Aspell is designed to be a drop-in replacement for Ispell.