diff --git a/blocks/admin_tree/block_admin_tree.php b/blocks/admin_tree/block_admin_tree.php
index ed2f377d01f..dc495715c86 100644
--- a/blocks/admin_tree/block_admin_tree.php
+++ b/blocks/admin_tree/block_admin_tree.php
@@ -122,6 +122,9 @@ class block_admin_tree extends block_base {
         }
 
         if ($this->tempcontent !== '') {
+            $strfolderopened = s(get_string('folderopened'));
+            $strfolderclosed = s(get_string('folderclosed'));
+
             $this->content = new stdClass;
             $this->content->text  = '<script type="text/javascript">'."\n";
             $this->content->text .= '<!--' . "\n";
@@ -139,11 +142,11 @@ class block_admin_tree extends block_base {
             $this->content->text .= 'function toggle(spanid) {' . "\n";
             $this->content->text .= '  if (getspan(spanid).innerHTML == "") {' . "\n";
             $this->content->text .= '    getspan(spanid).innerHTML = vh_content[spanid];' . "\n";
-            $this->content->text .= '    getspan(spanid + "indicator").innerHTML = \'<img src="' . $CFG->wwwroot . '/blocks/admin_tree/open.gif" border="0" alt="[open folder]" />\';' . "\n";
+            $this->content->text .= '    getspan(spanid + "indicator").innerHTML = \'<img src="' . $CFG->wwwroot . '/blocks/admin_tree/open.gif" border="0" alt="'.$strfolderopened.'" />\';' . "\n";
             $this->content->text .= '  } else {' . "\n";
             $this->content->text .= '    vh_content[spanid] = getspan(spanid).innerHTML;' . "\n";
             $this->content->text .= '    getspan(spanid).innerHTML = "";' . "\n";
-            $this->content->text .= '    getspan(spanid + "indicator").innerHTML = \'<img src="' . $CFG->wwwroot . '/blocks/admin_tree/closed.gif" border="0" alt="[closed folder]" />\';' . "\n";
+            $this->content->text .= '    getspan(spanid + "indicator").innerHTML = \'<img src="' . $CFG->wwwroot . '/blocks/admin_tree/closed.gif" border="0" alt="'.$strfolderclosed.'" />\';' . "\n";
             $this->content->text .= '  }' . "\n";
             $this->content->text .= '}' . "\n";
 
@@ -151,13 +154,13 @@ class block_admin_tree extends block_base {
             $this->content->text .= '  if (getspan(spanid).innerHTML !== "") {' . "\n";
             $this->content->text .= '    vh_content[spanid] = getspan(spanid).innerHTML;' . "\n";
             $this->content->text .= '    getspan(spanid).innerHTML = "";' . "\n";
-            $this->content->text .= '    getspan(spanid + "indicator").innerHTML = \'<img src="' . $CFG->wwwroot . '/blocks/admin_tree/closed.gif" border="0" alt="[closed folder]" />\';' . "\n";
+            $this->content->text .= '    getspan(spanid + "indicator").innerHTML = \'<img src="' . $CFG->wwwroot . '/blocks/admin_tree/closed.gif" border="0" alt="'.$strfolderclosed.'" />\';' . "\n";
             $this->content->text .= '  }' . "\n";
             $this->content->text .= '}' . "\n";
 
             $this->content->text .= 'function expand(spanid) {' . "\n";
             $this->content->text .= '  getspan(spanid).innerHTML = vh_content[spanid];' . "\n";
-            $this->content->text .= '  getspan(spanid + "indicator").innerHTML = \'<img src="' . $CFG->wwwroot . '/blocks/admin_tree/open.gif" border="0" alt="[open folder]" />\';' . "\n";
+            $this->content->text .= '  getspan(spanid + "indicator").innerHTML = \'<img src="' . $CFG->wwwroot . '/blocks/admin_tree/open.gif" border="0" alt="'.$strfolderopened.'" />\';' . "\n";
             $this->content->text .= '}' . "\n";
 
             $this->content->text .= 'function expandall() {' . "\n";
diff --git a/lang/en_utf8/moodle.php b/lang/en_utf8/moodle.php
index 1817acd0a27..e094cee5d96 100644
--- a/lang/en_utf8/moodle.php
+++ b/lang/en_utf8/moodle.php
@@ -552,6 +552,8 @@ $string['findmorecourses'] = 'Find more courses...';
 $string['firstdayofweek'] = '0';
 $string['firstname'] = 'First name';
 $string['firsttime'] = 'Is this your first time here?';
+$string['folderopened'] = 'Opened folder';
+$string['folderclosed'] = 'Closed folder';
 $string['followingoptional'] = 'The following items are optional';
 $string['followingrequired'] = 'The following items are required';
 $string['force'] = 'Force';