Backend\Core\Engine\Cronjob::setLanguage PHP Method

    public function setLanguage($value)
    {
        // get the possible languages
        $possibleLanguages = BackendLanguage::getWorkingLanguages();
        // validate
        if (!array_key_exists($value, $possibleLanguages)) {
            throw new Exception('Invalid language.');
        }
        // set property
        $this->language = $value;
        // set the locale (we need this for the labels)
        BackendLanguage::setLocale($this->language);
        // set working language
        BackendLanguage::setWorkingLanguage($this->language);
    }