Link titles on multilingual websites

The text needs to be run through the t() function to make it available to the translation system. So, if you just add the t() function anywhere you return something like $element['#item']['display_title'] it should become translatable.

For instance:

--- link.module (saved version)
+++ (current document)
@@ -536,11 +536,11 @@
 function theme_link_formatter_default($element) {
   // Display a normal link if both title and URL are available.
   if (!empty($element['#item']['display_title']) && !empty($element['#item']['url'])) {
-    return l($element['#item']['display_title'], $element['#item']['url'], $element['#item']);
+    return l(t($element['#item']['display_title']), $element['#item']['url'], $element['#item']);
   }
   // If only a title, display the title.
   elseif (!empty($element['#item']['display_title'])) {
-    return check_plain($element['#item']['display_title']);
+    return check_plain(t($element['#item']['display_title']));
   }
 }
 
@@ -581,7 +581,7 @@
 
   $output = '';
   $output .= '<div class="link-item '. $class .'">';
-  $output .= '<div class="link-title">'. (empty($element['#item']['title']) ? '' : $element['#item']['display_title']) .'</div>';
+  $output .= '<div class="link-title">'. (empty($element['#item']['title']) ? '' : t($element['#item']['display_title'])) .'</div>';
   $output .= '<div class="link-url">'. l($element['#item']['display_url'], $element['#item']['url'], $element['#item']) .'</div>';
   $output .= '</div>';
   return $output;