I am using the FJRelated plugin. There is a menu item for fjrelated to display a page almost the same as Joomla's default Category List.
I have this line:
<?php echo JHtml::_('grid.sort', 'COM_FJRELATED_'.$date.'_DATE', $dateOrder, $listDirn, $listOrder); ?>
which I change to:
<?php echo JHtml::_('grid.sort', 'COM_CONTENT_'.$date.'_DATE', $dateOrder, $listDirn, $listOrder); ?>
but in the front end I see the string COM_CONTENT_CREATED_DATE instead of the actual translation.
In Joomla's default_articles.php there is the same line:
<?php echo JHtml::_('grid.sort', 'COM_CONTENT_' . $date . '_DATE', 'a.created', $listDirn, $listOrder); ?>
which works perfectly fine in the front end.
I do not remember anything else to be needed in order to use Joomla's language strings in any custom php page. What am I doing wrong?