protected function mergeModuleTranslations($langcode = null)
    {
        $modules = $this->module->getEnabled();

        // Sort modules in descending order
        // More important modules go first so their translations will be added earlier
        gplcart_array_sort($modules, 'weight', false);

        foreach ($modules as $module) {
            $file = $this->getFile($langcode, $module['module_id']);
            if (is_file($file)) {
                $this->mergeTranslation($file, $langcode);
            }
        }
    }