If aicontactsafe_2.0.19 form and Jcomments form used on the same page, the values of the language constants for Jcomments form are not shown (not output).
The reason is the following code, added to the files - mod_aicontactsafe.php and plg_aicontactsafeform/aicontactsafeform.php in 2.0.19:
// Load the language file of com_aicontactsafe
$lang =& JFactory::getLanguage ();
$please_wait_text = JText::_('COM_AICONTACTSAFE_PLEASE_WAIT');
If you comment out this code snippet (/ * ... * /), then everything appears Ok for Jcomments form.