In some lang-files is the key declaration in arrays unclean
Check this:
http://de.php.net/manual/en/language.types.array.php
"Array do's and don'ts"
"Why is $foo[bar] wrong?"
this is unclean code:
$lang[encoding] = 'utf-8';
$lang[direction] = 'ltr';
use better this:
$lang['encoding'] = 'utf-8';
$lang['direction'] = 'ltr';