private function setLanguageKeyFromConfiguration(\Tx_Oelib_Configuration $configuration)
    {
        if (!$configuration->hasString('language')) {
            return;
        }

        $this->languageKey = $configuration->getAsString('language');
        if ($configuration->hasString('language_alt')) {
            $this->alternativeLanguageKey = $configuration->getAsString('language_alt');
        }
    }