Nuspell is a free and open source spell checker library and command-line program designed for languages with rich morphology and complex word compounding. Nuspell is a pure C++ re-implementation of Hunspell.

Main features of Nuspell spell checker:

Full unicode support backed by ICU
Backward compatibility with Hunspell dictionary file format
Twofold affix stripping (for agglutinative languages, like Azeri, Basque, Estonian, Finnish, Hungarian, Turkish, etc.)
Support complex compounds (for example, Hungarian, German and Dutch)
Support language specific features (for example, special casing of Azeri and Turkish dotted i, or German sharp s)
Handle conditional affixes, circumfixes, fogemorphemes, forbidden words, pseudoroots and homonyms.
Free software. Licensed under GNU LGPL v3 or later.