diff --git a/inc/mask.php b/inc/mask.php
index df9c2d2..f5ee98d 100755
--- a/inc/mask.php
+++ b/inc/mask.php
@@ -21,6 +21,7 @@ class Mask extends PhpObject
 	const START_TAG = 'START';
 	const END_TAG = 'END';
 	const TAG_MARK = '[#]';
+	const LANG_PREFIX = 'lang:';
 
 	public function __construct($sFileName='', Translator $oLang=null)
 	{
@@ -184,7 +185,8 @@ class Mask extends PhpObject
 	public function getTags($bLang=false)
 	{
 		$sSafeTagMark = preg_quote(self::TAG_MARK);
-		$sPattern = '/'.$sSafeTagMark.'(?P<tag>(lang\:|)\w+)'.$sSafeTagMark.'/u';
+		$sSafeLangMark = preg_quote(self::LANG_PREFIX);
+		$sPattern = '/'.$sSafeTagMark.'(?P<tag>('.$sSafeLangMark.'|)\w+)'.$sSafeTagMark.'/u';
 		preg_match_all($sPattern, $this->sMask, $asMatches);
 		return array_unique(array_filter($asMatches['tag']));
 	}
@@ -217,7 +219,7 @@ class Mask extends PhpObject
 	}
 	
 	private static function isLangTag($sTag) {
-		return (mb_substr($sTag, 0, 5) == 'lang:');
+		return (mb_substr($sTag, 0, 5) == self::LANG_PREFIX);
 	}
 
 	public function getMask()