Document.SpellingErrors (Word)

Returns a ProofreadingErrors collection that represents the words identified as spelling errors in the specified document or range.

For information about returning a single member of a collection, see Returning an object from a collection.

myErr = ActiveDocument.SpellingErrors.Count 
If myErr = 0 Then 
 Msgbox "No spelling errors found." 
Else 
 Msgbox myErr & " spelling errors found." 
End If