/**
  * Sets the currently active language/language_alt keys.
  * Default values are "default" for language key and "" for language_alt key.
  *
  * @return void
  */
 protected static function setLanguageKeys()
 {
     self::$languageKey = 'default';
     self::$alternativeLanguageKeys = array();
     if (TYPO3_MODE === 'FE') {
         if (isset($GLOBALS['TSFE']->config['config']['language'])) {
             self::$languageKey = $GLOBALS['TSFE']->config['config']['language'];
             if (isset($GLOBALS['TSFE']->config['config']['language_alt'])) {
                 self::$alternativeLanguageKeys[] = $GLOBALS['TSFE']->config['config']['language_alt'];
             } else {
                 /** @var $locales \TYPO3\CMS\Core\Localization\Locales */
                 $locales = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Core\Localization\Locales::class);
                 if (in_array(self::$languageKey, $locales->getLocales())) {
                     foreach ($locales->getLocaleDependencies(self::$languageKey) as $language) {
                         self::$alternativeLanguageKeys[] = $language;
                     }
                 }
             }
         }
     } elseif ($GLOBALS['BE_USER']->uc['lang'] !== '') {
         self::$languageKey = $GLOBALS['BE_USER']->uc['lang'];
     }
 }
 /**
  * Sets the currently active language/language_alt keys.
  * Default values are "default" for language key and "" for language_alt key.
  *
  * @return void
  */
 protected static function setLanguageKeys()
 {
     self::$languageKey = 'default';
     self::$alternativeLanguageKeys = array();
     if (TYPO3_MODE === 'FE') {
         if (isset(self::getTypoScriptFrontendController()->config['config']['language'])) {
             self::$languageKey = self::getTypoScriptFrontendController()->config['config']['language'];
             if (isset(self::getTypoScriptFrontendController()->config['config']['language_alt'])) {
                 self::$alternativeLanguageKeys[] = self::getTypoScriptFrontendController()->config['config']['language_alt'];
             } else {
                 /** @var $locales \TYPO3\CMS\Core\Localization\Locales */
                 $locales = GeneralUtility::makeInstance(Locales::class);
                 if (in_array(self::$languageKey, $locales->getLocales())) {
                     foreach ($locales->getLocaleDependencies(self::$languageKey) as $language) {
                         self::$alternativeLanguageKeys[] = $language;
                     }
                 }
             }
         }
     } elseif (!empty($GLOBALS['BE_USER']->uc['lang'])) {
         self::$languageKey = $GLOBALS['BE_USER']->uc['lang'];
     } elseif (!empty(self::getLanguageService()->lang)) {
         self::$languageKey = self::getLanguageService()->lang;
     }
 }