aspell – Spell checker

GNU Aspell is a Free and Open Source spell checker de­signed to re­place Ispell. It can ei­ther be used as a li­brary or as an in­de­pen­dent spell checker. Its main fea­ture is that it does a su­pe­rior job of sug­gest­ing pos­si­ble re­place­ments for a mis­spelled word than just about any other spell checker out there for the English lan­guage. Aspell can check doc­u­ments in UTF-8 with­out hav­ing to use a spe­cial dic­tio­nary; and will do its best to re­spect the cur­rent lo­cale set­ting.
A wide range of lan­guage-spe­cific dic­tio­nar­ies is avail­able.