Hello, I leave this message because this changeset had been fully reverted by another mapper in https://www.openstreetmap.org/changeset/169621588
and I thinks you shouldn't add other language's name in a area currently been actually controlled by a specific country. For example, I know that Viet Nam have a claim about South China Sea, and some of its island, also many other country such as Malaysia, Philippine,  Brunei, have opinion about this. But OSM only handle with actually control, that is, if China still control those island (even have resident and force on it), it will be seen as part of China on OSM. So at this time, please don't add Vietnamese name to it.