Hunspell

Hunspell is the spell checker of LibreOffice, OpenOffice.org and Mozilla Firefox 3 & Thunderbird, Google Chrome, and it is also used by proprietary softwares, like Mac OS X, memoQ, Opera and SDL Trados.

• Extended support for language peculiarities;
  Unicode character encoding, compounding and complex morphology.
• Improved suggestion using n-gram similarity, rule and dictionary based pronounciation data.
• Morphological analysis, stemming and generation.
• Hunspell is based on MySpell and works also with MySpell dictionaries.
• C++ library under GPL/LGPL/MPL tri-license.
• Interfaces and ports:
  Enchant (Generic spelling library from the Abiword project), XSpell (Mac OS X port, but Hunspell is part of the OS X from version 10.6 (Snow Leopard), and now it is enough to place Hunspell dictionary files into ~/Library/Spelling or /Library/Spelling for spell checking), Delphi, Java (JNA, JNI), Perl,
  .NET,
  Python, Ruby ([1], [2], [3]), UNO.
• It uses local dictionary sources, so no outside connection is required

• Local dictionary sources, no need for outside connections
• Easy to use and to replace and use other dictionary languages. Just go to OpenOffice Dictionaries and download your language "oxt"; rename it to "zip" and extract two files with "aff" and "dic" extensions; load them into your hunspell eSpace resources and start using

• Needs some optimization's when breaking the text to do the spell checking