I've some code that sets the lang var towards the site default language.

$lg = &JFactory::getLanguage();
$lg = explode('-',$lg->_default);
$dlg = $lg[0];
if(!JRequest::getWord('lang', false ))
    JRequest::setVar('lang', $dlg );

however before setting it to $dlg I must discover when the language is saved within the user information or session.

Can someone let me know how to determine the session for language information?

$lg = &JFactory::getLanguage();
$lg = explode('-',$lg->_lang);
$dlg = $lg[0];
if(!JRequest::getWord('lang', false ))
    JRequest::setVar('lang', $dlg );

i needed to just change it out from _default to _lang