zentao/extension/or/todo/ext/lang/en/or.php

<?php
$lang->todo->typeList = array();
$lang->todo->typeList['custom']      = 'Custom';
$lang->todo->typeList['demand']      = 'Demand';
$lang->todo->typeList['requirement'] = $lang->URCommon;
$lang->todo->typeList['task']        = 'Task';
$lang->todo->typeList['feedback']    = 'Feedback';