You can check the spelling of your 4D Write document manually through the menu command or automatically through a setting in document preferences. To check manually, click on "Spelling" from the Tools menu or press F7 on Windows and Cmd+Shift+N on Mac OS X. A dialog will come up which shows words that could possibly be misspelled and some spelling suggestions. To check automatically, check the "Checking as you type" option of the Spellchecker settings in the Document Preferences of 4D Write under the File menu. With this option selected, the words entered will be checked as you type. The words that could possibly misspelled will have a red wavy underline.