ImTranslator blog

The spell checker chooses the language according to the selected language pair. For example, if the language combination selected for translation is English-Russian, then the spelling language for the source window is English and for the target window is Russian. You can suggest the language of the text manually via the Dictionary Language dropdown box inside the speller dialog box.
The spell-checking dialog will flag in bold blue misspelled words and provide a list of suggestions.

In case of a mixed text, you can change the spelling language on-the-fly from the Dictionary Language dropdown box and continue the spell-checking session.
The Options button allows you to set spell-checking options that affect the way the spell-checker works.
The Add to Dictionary option allows you add unknown words to the user dictionary which is stored in cookies on your computer.

The Auto functions if checked, automatically performs the following task:
Enables automatic Spell Checker. Auto spell checker detects spelling errors, and offers the option to change, ignore, or correct misspelled words.