Spell checking is not available for formatted notifications.
To spell check plain text notifications:
With a plain text notification open in the notification editor, in the Options ribbon group of the Notifications tab, click Spell Check.
The Spell Check dialog is displayed.
Evaluate the highlighted word to determine if it is misspelled.
If the word is not misspelled, click Ignore to accept that instance of the word, or Ignore All to accept all instances of the word in the notification.
If it is misspelled, you can choose one of the suggestions listed.
Click Change to change the single instance of the misspelled word.
Click Change All to change every instance of the misspelled word to the selected choice.
If the desired word is not listed in the suggestions, you can enter your own text in the Use this instead: field.
Once you are finished checking the notification, click OK to close the dialog.