chamilo-lms/public/plugin/hello_world/index.php

<?php

// See also the share_user_info plugin

echo '<div class="well">';
if (!empty($plugin_info['settings']['hello_world_show_type'])) {
    echo '<h2>'.$plugin_info['settings']['hello_world_show_type'].'</h2>';
} else {
    echo '<h2>Hello world</h2>';
}

//Using get_lang inside a plugin
echo get_lang('HelloPlugin');

echo '</div>';