EmEditor uses the Hunspell library, also used by applications such as OpenOffice and Firefox, to check spelling in multiple languages. With Camel Case support, EmEditor also lets you check for misspellings in variable/function names.
As you type, misspelled words are marked with red wiggly underlines. EmEditor allows you to correct misspelled words quickly and easily. The EmEditor installer includes a U.S. English dictionary by default. Additional dictionaries are available for download at the OpenOffice.org. After download a dictionary, change the file extension from .oxt to .zip, extract the Zip file, and then copy *.dic and *.aff files into the Dictionaries sub folder of the EmEditor install folder (usually C:\Program Files\EmEditor\Dictionaries).