protected function _getLanguage($sourceSurveyId, $language)
    {
        if (! is_string($language)) {
            $language = (string) $language;
        }

        if (! isset($this->_languageMap[$sourceSurveyId][$language])) {
            if ($language && $this->_isLanguage($sourceSurveyId, $language)) {
                $this->_languageMap[$sourceSurveyId][$language] = $language;
            } else {
                $lsDb = $this->getSourceDatabase();

                $sql = 'SELECT language
                    FROM ' . $this->_getSurveysTableName() . '
                    WHERE sid = ?';

                $this->_languageMap[$sourceSurveyId][$language] = $lsDb->fetchOne($sql, $sourceSurveyId);
            }
        }

        return $this->_languageMap[$sourceSurveyId][$language];
    }