--- a/runtime/doc/spell.txt
+++ b/runtime/doc/spell.txt
@@ -1,4 +1,4 @@
-*spell.txt*	For Vim version 7.0aa.  Last change: 2005 Aug 29
+*spell.txt*	For Vim version 7.0aa.  Last change: 2005 Aug 30
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -64,13 +64,19 @@ To add words to your own word list:				*
 
 							*zg*
 zg			Add word under the cursor as a good word to the first
-			name in 'spellfile'.  In Visual mode the selected
-			characters are added as a word (including white
-			space!).  If the word is explicitly marked as bad word
-			in another spell file the result is unpredictable.
-			A count may precede the command to indicate the entry
-			in 'spellfile' to be used.  A count of two uses the
-			second entry.
+			name in 'spellfile'.  A count may precede the command
+			to indicate the entry in 'spellfile' to be used.  A
+			count of two uses the second entry.
+
+			In Visual mode the selected characters are added as a
+			word (including white space!).
+			When the cursor is on text that is marked as badly
+			spelled then the marked text is used.
+			Otherwise the word under the cursor, separated by
+			non-word characters, is used.
+
+			If the word is explicitly marked as bad word in
+			another spell file the result is unpredictable.
 
 							*zG*
 zG			Like "zg" but add the word to the internal word list