If the System Administrator has configured one or several Spell Checkers, the Composer page contains the Check Spelling button with the list of available Spell Checkers (languages).
Select the language and click the Check Spelling button to check the message text. If the selected Spell Checker finds a word it cannot recognize, the Spell Checker panel appears:
The panel contains a highlighted unrecognized word within surrounding text. Click the Ignore button to continue checking. If the Spell Checker program can suggest changes, the Change to button appears with a menu of the suggestions. Click the Change to button to use the selected suggestion and to continue the spelling check process.