diff --git a/lisp/help.el b/lisp/help.el
index 7902a5c5b14..b384c476eb3 100644
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -1449,10 +1449,11 @@ Otherwise, return a new string."
         (buffer-string)))))
 
 (defun substitute-quotes (string)
-  "Substitute quote characters for display.
+  "Substitute quote characters in STRING for display.
 Each grave accent \\=` is replaced by left quote, and each
-apostrophe \\=' is replaced by right quote.  Left and right quote
-characters are specified by `text-quoting-style'."
+apostrophe \\=' is replaced by right quote.  Which left and right
+quote characters to use is determined by the variable
+`text-quoting-style'."
   (cond ((eq (text-quoting-style) 'curve)
          (string-replace "`" "‘"
                          (string-replace "'" "’" string)))