code: protected function getSpellcheckerString()
  	{
  		System::loadLanguageFile('languages');
  
  		$return = array();
  		$langs = scan(__DIR__ . '/../../languages');
  		array_unshift($langs, $GLOBALS['TL_LANGUAGE']);
  
  		foreach ($langs as $lang)
  		{
  			$lang = substr($lang, 0, 2);
  
  			if (isset($GLOBALS['TL_LANG']['LNG'][$lang]))
  			{
  				$return[$lang] = $GLOBALS['TL_LANG']['LNG'][$lang] . '=' . $lang;
  			}
  		}
  
  		return '+' . implode(',', array_unique($return));
  	}
docs: Return the languages for the TinyMCE spellchecker
  
  @return string The TinyMCE spellchecker language string