public function getDefaultLanguage()
    {
        if (!$this->defaultLanguage) {
            $language = substr(setlocale(LC_ALL, 0), 0, 2);
            $languages = $this->getLanguages();
            $languageDefault = reset($languages);
            $language = $this->isValidLanguage($language) ? $language : $languageDefault;
            $this->setDefaultLanguage($language);
        }

        return $this->defaultLanguage;
    }