diff --git a/modules/block/block.module b/modules/block/block.module
index f56e428dc94cf8aee3a9af602488708ec3d87568..9c482e1de10f1bd470146f2a07920c81c6110292 100644
--- a/modules/block/block.module
+++ b/modules/block/block.module
@@ -213,7 +213,7 @@ function block_block($op = 'list', $delta = 0, $edit = array()) {
 
     case 'view':
       $block = db_fetch_object(db_query('SELECT body, format FROM {boxes} WHERE bid = %d', $delta));
-      $data['content'] = check_markup($block->body, $block->format, FALSE);
+      $data['content'] = check_markup($block->body, $block->format, '', FALSE);
       return $data;
   }
 }
diff --git a/modules/comment/comment.module b/modules/comment/comment.module
index 7644e0f9eefdad27216663c9b0b1bd3aa6c044e5..d1797fef8a5868af2549c8eccb35b1dd7c374e39 100644
--- a/modules/comment/comment.module
+++ b/modules/comment/comment.module
@@ -604,7 +604,7 @@ function comment_nodeapi_update_index(&$node, $arg = 0) {
   $text = '';
   $comments = db_query('SELECT subject, comment, format FROM {comments} WHERE nid = %d AND status = %d', $node->nid, COMMENT_PUBLISHED);
   while ($comment = db_fetch_object($comments)) {
-    $text .= '<h2>' . check_plain($comment->subject) . '</h2>' . check_markup($comment->comment, $comment->format, FALSE);
+    $text .= '<h2>' . check_plain($comment->subject) . '</h2>' . check_markup($comment->comment, $comment->format, '', FALSE);
   }
   return $text;
 }
@@ -1597,7 +1597,7 @@ function theme_comment_view($comment, $node, $links = array(), $visible = TRUE)
 
   // Switch to folded/unfolded view of the comment.
   if ($visible) {
-    $comment->comment = check_markup($comment->comment, $comment->format, FALSE);
+    $comment->comment = check_markup($comment->comment, $comment->format, '', FALSE);
     // Comment API hook.
     comment_invoke_comment($comment, 'view');
     $output .= theme('comment', $comment, $node, $links);
diff --git a/modules/filter/filter.module b/modules/filter/filter.module
index 8366216b4ccc2da04b4d95186f84660983b6ada4..7e21d5facb255c1eac18087362b34eb748522c2b 100644
--- a/modules/filter/filter.module
+++ b/modules/filter/filter.module
@@ -409,6 +409,10 @@ function filter_list_format($format) {
  * @param $format
  *    The format of the text to be filtered. Specify FILTER_FORMAT_DEFAULT for
  *    the default format.
+ * @param $langcode
+ *    Optional: the language code of the text to be filtered, e.g. 'en' for
+ *    English.  This allows filters to be language aware so language specific
+ *    text replacement can be implemented.
  * @param $check
  *    Whether to check the $format with filter_access() first. Defaults to TRUE.
  *    Note that this will check the permissions of the current user, so you
@@ -416,13 +420,13 @@ function filter_list_format($format) {
  *    showing content that is not (yet) stored in the database (eg. upon preview),
  *    set to TRUE so the user's permissions are checked.
  */
-function check_markup($text, $format = FILTER_FORMAT_DEFAULT, $check = TRUE) {
+function check_markup($text, $format = FILTER_FORMAT_DEFAULT, $langcode = '', $check = TRUE) {
   // When $check = TRUE, do an access check on $format.
   if (isset($text) && (!$check || filter_access($format))) {
     $format = filter_resolve_format($format);
 
     // Check for a cached version of this piece of text.
-    $cache_id = $format . ':' . md5($text);
+    $cache_id = $format . ':' . $langcode . ':' . md5($text);
     if ($cached = cache_get($cache_id, 'cache_filter')) {
       return $cached->data;
     }
@@ -439,12 +443,12 @@ function check_markup($text, $format = FILTER_FORMAT_DEFAULT, $check = TRUE) {
 
     // Give filters the chance to escape HTML-like data such as code or formulas.
     foreach ($filters as $filter) {
-      $text = module_invoke($filter->module, 'filter', 'prepare', $filter->delta, $format, $text, $cache_id);
+      $text = module_invoke($filter->module, 'filter', 'prepare', $filter->delta, $format, $text, $langcode, $cache_id);
     }
 
     // Perform filtering.
     foreach ($filters as $filter) {
-      $text = module_invoke($filter->module, 'filter', 'process', $filter->delta, $format, $text, $cache_id);
+      $text = module_invoke($filter->module, 'filter', 'process', $filter->delta, $format, $text, $langcode, $cache_id);
     }
 
     // Store in cache with a minimum expiration time of 1 day.
diff --git a/modules/node/node.module b/modules/node/node.module
index eed4cf34aad9cc45f725f55438b9ca61da007b22..7c8763cd3d873a33f48d176c25fe3b745c9b3a4c 100644
--- a/modules/node/node.module
+++ b/modules/node/node.module
@@ -1088,10 +1088,10 @@ function node_prepare($node, $teaser = FALSE) {
   $node->readmore = (strlen($node->teaser) < strlen($node->body));
 
   if ($teaser == FALSE) {
-    $node->body = check_markup($node->body, $node->format, FALSE);
+    $node->body = check_markup($node->body, $node->format, $node->language, FALSE);
   }
   else {
-    $node->teaser = check_markup($node->teaser, $node->format, FALSE);
+    $node->teaser = check_markup($node->teaser, $node->format, $node->language, FALSE);
   }
 
   $node->content['body'] = array(