diff --git a/phpBB/adm/style/acp_language.html b/phpBB/adm/style/acp_language.html
index faf8159b49..4439f519e0 100644
--- a/phpBB/adm/style/acp_language.html
+++ b/phpBB/adm/style/acp_language.html
@@ -36,46 +36,32 @@
 	</fieldset>
 	</form>
 
-	<br /><br />
+	<!-- IF .missing_files -->
+		<h3 class="error">{L_MISSING_FILES}</h3>
 
-	<!-- IF S_MISSING_FILES -->
-		<div class="errorbox">
-			<h3>{L_MISSING_FILES}</h3>
-			<p>{MISSING_FILES}</p>
-		</div>
-		<br /><br />
+		<fieldset>
+			<legend>{L_MISSING_LANG_FILES}</legend>
+			<!-- BEGIN missing_files -->
+			&raquo; {missing_files.FILE_NAME}<br />
+			<!-- END missing_files -->
+		</fieldset>
 	<!-- ENDIF -->
 
-	<!-- IF S_MISSING_VARS -->
-		<h1>{L_MISSING_LANG_VARIABLES}</h1>
+	<!-- IF .missing_varfile -->
+		<h3 class="error">{L_MISSING_VARS_EXPLAIN}</h3>
 
-		<p>{L_MISSING_VARS_EXPLAIN}</p>
-
-		<form id="missing" method="post" action="{U_MISSING_ACTION}">
-
-		<table class="table1">
-		<thead>
-		<tr>
-			<th>{L_LANGUAGE_KEY}</th>
-			<th>{L_LANGUAGE_VARIABLE}</th>
-		</tr>
-		</thead>
-		<tbody>
-		<!-- BEGIN missing -->
-			<tr class="row4">
-				<td><strong>{missing.FILE}</strong></td>
-				<td style="text-align: right;"><input type="submit" name="missing_file[{missing.KEY}]" value="{L_SELECT}" class="button2" /></td>
-			</tr>
-			{missing.TPL}
-		<!-- END missing -->
-		</tbody>
-		</table>
-		<div>{S_FORM_TOKEN}</div>
-		</form>
-
-		<br /><br />
+		<fieldset>
+			<legend>{L_MISSING_LANG_VARIABLES}</legend>
+			<!-- BEGIN missing_varfile -->
+			<dl>
+				<dt><label>{missing_varfile.FILE_NAME}</label></dt>
+				<!-- BEGIN variable -->
+				<dd>{missing_varfile.variable.VAR_NAME}</dd>
+				<!-- END variable -->
+			</dl>
+			<!-- END missing_varfile -->
+		</fieldset>
 	<!-- ENDIF -->
-
 <!-- ELSE -->
 
 	<h1>{L_ACP_LANGUAGE_PACKS}</h1>
diff --git a/phpBB/includes/acp/acp_language.php b/phpBB/includes/acp/acp_language.php
index d0920c3490..dfd3b06290 100644
--- a/phpBB/includes/acp/acp_language.php
+++ b/phpBB/includes/acp/acp_language.php
@@ -110,6 +110,8 @@ class acp_language
 				$lang_entries = $db->sql_fetchrow($result);
 				$db->sql_freeresult($result);
 
+				$lang_iso = $lang_entries['lang_iso'];
+
 				$template->assign_vars(array(
 					'S_DETAILS'			=> true,
 					'U_ACTION'			=> $this->u_action . "&amp;action=details&amp;id=$lang_id",
@@ -117,10 +119,67 @@ class acp_language
 
 					'LANG_LOCAL_NAME'	=> $lang_entries['lang_local_name'],
 					'LANG_ENGLISH_NAME'	=> $lang_entries['lang_english_name'],
-					'LANG_ISO'			=> $lang_entries['lang_iso'],
+					'LANG_ISO'			=> $lang_iso,
 					'LANG_AUTHOR'		=> $lang_entries['lang_author'],
+					'L_MISSING_FILES'			=> $user->lang('THOSE_MISSING_LANG_FILES', $lang_entries['lang_local_name']),
+					'L_MISSING_VARS_EXPLAIN'	=> $user->lang('THOSE_MISSING_LANG_VARIABLES', $lang_entries['lang_local_name']),
 				));
 
+				// If current lang is different from the default lang, then highlight missing files and variables
+				if ($lang_iso != $config['default_lang'])
+				{
+					try
+					{
+						$iterator = new \RecursiveIteratorIterator(
+							new \phpbb\recursive_dot_prefix_filter_iterator(
+								new \RecursiveDirectoryIterator(
+									$phpbb_root_path . 'language/' . $config['default_lang'] . '/',
+									\FilesystemIterator::SKIP_DOTS
+								)
+							),
+							\RecursiveIteratorIterator::LEAVES_ONLY
+						);
+					}
+					catch (\Exception $e)
+					{
+						return array();
+					}
+
+					foreach ($iterator as $file_info)
+					{
+						/** @var \RecursiveDirectoryIterator $file_info */
+						$relative_path = $iterator->getInnerIterator()->getSubPathname();
+						$relative_path = str_replace(DIRECTORY_SEPARATOR, '/', $relative_path);
+
+						if (file_exists($phpbb_root_path . 'language/' . $lang_iso . '/' . $relative_path))
+						{
+							if (substr($relative_path, 0 - strlen($phpEx)) === $phpEx)
+							{
+								$missing_vars = $this->compare_language_files($config['default_lang'], $lang_iso, $relative_path);
+
+								if (!empty($missing_vars))
+								{
+									$template->assign_block_vars('missing_varfile', array(
+										'FILE_NAME'			=> $relative_path,
+									));
+
+									foreach ($missing_vars as $var)
+									{
+										$template->assign_block_vars('missing_varfile.variable', array(
+												'VAR_NAME'			=> $var,
+										));
+									}
+								}
+							}
+						}
+						else
+						{
+							$template->assign_block_vars('missing_files', array(
+								'FILE_NAME' => $relative_path,
+							));
+						}
+					}
+				}
 				return;
 			break;
 
@@ -362,4 +421,32 @@ class acp_language
 
 		unset($new_ary);
 	}
+
+	/**
+	* Compare two language files
+	*/
+	function compare_language_files($source_lang, $dest_lang, $file)
+	{
+		global $phpbb_root_path;
+
+		$source_file = $phpbb_root_path . 'language/' . $source_lang . '/' . $file;
+		$dest_file = $phpbb_root_path . 'language/' . $dest_lang . '/' . $file;
+
+		if (!file_exists($dest_file))
+		{
+			return array();
+		}
+
+		$lang = array();
+		include($source_file);
+		$lang_entry_src = $lang;
+
+		$lang = array();
+		include($dest_file);
+		$lang_entry_dst = $lang;
+
+		unset($lang);
+
+		return array_diff(array_keys($lang_entry_src), array_keys($lang_entry_dst));
+	}
 }
diff --git a/phpBB/language/en/acp/language.php b/phpBB/language/en/acp/language.php
index 154551bd6e..5df99892ca 100644
--- a/phpBB/language/en/acp/language.php
+++ b/phpBB/language/en/acp/language.php
@@ -71,6 +71,7 @@ $lang = array_merge($lang, array(
 	'LANG_LOCAL_NAME'					=> 'Local name',
 
 	'MISSING_LANGUAGE_FILE'		=> 'Missing language file: <strong style="color:red">%s</strong>',
+	'MISSING_LANG_FILES'		=> 'Missing language files',
 	'MISSING_LANG_VARIABLES'	=> 'Missing language variables',
 	'MODS_FILES'				=> 'MODs language files',