Joomla Tags Fatal Error

Within the Article Manager Options > Articles tab, I set Show Tags to Show. Then, when clicking on a tag within the article content, I got the following error:

Fatal error: Call to a member function get() on a non-object in [ABSOLUTE SERVER PATH TO ACTIVE TEMPLATE DIRECTORY]/index.php on line 23

Unfortunately, fixing this error requires modifying a core Joomla file that will get overwritten with each update, so be sure to make a note of the modification.

In /libraries/cms/application/site.php, locate that line that reads:

$tag = $this->getLanguage()->getTag();

and change it to:

$tag = JFactory::getLanguage()->getTag();