chamilo-lms2/plugin/hello_world/lang/english.php

<?php
/**
 *
 * @copyright (c) 2012 University of Geneva
 * @license GNU General Public License - http://www.gnu.org/copyleft/gpl.html
 * @author Laurent Opprecht <laurent@opprecht.info>
 */

$strings['HelloPlugin'] = "Hello!";