From KEDMI Scientific Computing:
TinySpell+ Portable allows you to easily and quickly check and correct the spelling of words in any Windows application. It can watch your typing on-the-fly and alert you whenever it detects a misspelled word. It can also check the spelling of the text you copy to the clipboard. It comes with an American-English dictionary and supports Hunspell dictionaries in many languages. TinySpell+ Portable can be installed on portable drives.