}
        }

        for (final String f : langFields) {
            final String lf = f + "_" + language;
            if (doc.containsKey(f) && !doc.containsKey(lf)) {
                doc.put(lf, doc.get(f));
                if (logger.isDebugEnabled()) {
                    logger.debug("add {} field", lf);
                }
            }
        }
    }