zentao/module/projectplan/lang/en.php

<?php
$lang->projectplan = new stdclass();
$lang->projectplan->common  = "{$lang->projectCommon} Plan";
$lang->projectplan->browse  = "{$lang->projectCommon} Plan List";
$lang->projectplan->create  = "Create {$lang->projectCommon} Plan";
$lang->projectplan->edit    = "Edit {$lang->projectCommon} Plan";
$lang->projectplan->view    = "View {$lang->projectCommon} Plan";