diff --git a/lang/en/qtype_stack.php b/lang/en/qtype_stack.php
index 9b42883050021292f20c75caf4eecd50faa7e4c0..920f28d2fe8231bb2fd14a51915bdd89e8f4d11a 100644
--- a/lang/en/qtype_stack.php
+++ b/lang/en/qtype_stack.php
@@ -336,8 +336,8 @@ $string['questionvariablevalues'] = 'Question variable values';
 $string['quiet'] = 'Quiet';
 $string['quiet_help'] = 'When set to yes any feedback automatically generated by the answer tests is suppressed, and not displayed to the student.  The feedback fields in the branches are unaffected by this option.';
 // The icon fa-volume-off isn't very good really.
-$string['quiet_icon_true']  = '<span style="font-size: 1.25em; color:red;"><i class="fa fa-microphone-slash" aria-hidden="true"></i></span>';
-$string['quiet_icon_false'] = '<span style="font-size: 1.25em; color:blue;"><i class="fa fa-commenting-o"></i></span>';
+$string['quiet_icon_true']  = '<span title ="Quiet on" alt="Quiet On Microphone icon" style="font-size: 1.25em; color:red;"><i class="fa fa-microphone-slash" aria-hidden="true"></i></span>';
+$string['quiet_icon_false'] = '<span title ="Quiet off" alt="Quiet Off Microphone icon" "style="font-size: 1.25em; color:blue;"><i class="fa fa-commenting-o"></i></span>';
 $string['renamequestionparts'] = 'Rename parts of the question';
 $string['requiredfield'] = 'This field is required!';
 $string['requirelowestterms'] = 'Require lowest terms';